Merge branch 'siri/string-new-api'

* siri/string-new-api: (28 commits)
  hipe (test): Do not use deprecated functions in string(3)
  dialyzer (test): Do not use deprecated functions in string(3)
  eunit (test): Do not use deprecated functions in string(3)
  system (test): Do not use deprecated functions in string(3)
  system (test): Do not use deprecated functions in string(3)
  mnesia (test): Do not use deprecated functions in string(3)
  Deprecate old string functions
  observer: Do not use deprecated functions in string(3)
  common_test: Do not use deprecated functions in string(3)
  eldap: Do not use deprecated functions in string(3)
  et: Do not use deprecated functions in string(3)
  os_mon: Do not use deprecated functions in string(3)
  debugger: Do not use deprecated functions in string(3)
  runtime_tools: Do not use deprecated functions in string(3)
  asn1: Do not use deprecated functions in string(3)
  compiler: Do not use deprecated functions in string(3)
  sasl: Do not use deprecated functions in string(3)
  reltool: Do not use deprecated functions in string(3)
  kernel: Do not use deprecated functions in string(3)
  hipe: Do not use deprecated functions in string(3)
  ...

Conflicts:
	lib/eunit/src/eunit_lib.erl
	lib/observer/src/crashdump_viewer.erl
	lib/reltool/src/reltool_target.erl

120 files changed, 544 insertions, 933 deletions

diff --git a/erts/test/erlexec_SUITE.erl b/erts/test/erlexec_SUITE.erl
index 44d7f63387..db993abe52 100644
--- a/erts/test/erlexec_SUITE.erl
+++ b/erts/test/erlexec_SUITE.erl
@@ -59,7 +59,7 @@ otp_8209(Config) when is_list(Config) ->
     {ok,[[PName]]} = init:get_argument(progname),
     SNameS = "erlexec_test_01",
     SName = list_to_atom(SNameS++"@"++
-			 hd(tl(string:tokens(atom_to_list(node()),"@")))),
+			 hd(tl(string:lexemes(atom_to_list(node()),"@")))),
     Cmd = PName ++ " dummy_param -sname "++SNameS++" -setcookie "++
 	atom_to_list(erlang:get_cookie()),
     open_port({spawn,Cmd},[]),
@@ -75,7 +75,7 @@ cleanup_node(SNameS,0) ->
     {error, {would_not_die,list_to_atom(SNameS)}};
 cleanup_node(SNameS,N) ->
     SName = list_to_atom(SNameS++"@"++
-			 hd(tl(string:tokens(atom_to_list(node()),"@")))),
+			 hd(tl(string:lexemes(atom_to_list(node()),"@")))),
     case rpc:call(SName,init,stop,[]) of
 	{badrpc,_} ->
 	    ok;
@@ -322,7 +322,7 @@ zdbbl_dist_buf_busy_limit(Config) when is_list(Config) ->
     {ok,[[PName]]} = init:get_argument(progname),
     SNameS = "erlexec_test_02",
     SName = list_to_atom(SNameS++"@"++
-                         hd(tl(string:tokens(atom_to_list(node()),"@")))),
+                         hd(tl(string:lexemes(atom_to_list(node()),"@")))),
     Cmd = PName ++ " -sname "++SNameS++" -setcookie "++
         atom_to_list(erlang:get_cookie()) ++
 	" +zdbbl " ++ integer_to_list(LimKB),
@@ -400,7 +400,7 @@ emu_args(CmdLineArgs) ->
     {ok,[[Erl]]} = init:get_argument(progname),
     EmuCL = os:cmd(Erl ++ " -emu_args_exit " ++ CmdLineArgs),
     io:format("EmuCL = ~ts", [EmuCL]),
-    split_emu_clt(string:tokens(EmuCL, [$ ,$\t,$\n,$\r])).
+    split_emu_clt(string:lexemes(EmuCL, [$ ,$\t,$\n,$\r])).
 
 split_emu_clt(EmuCLT) ->
     split_emu_clt(EmuCLT, [], [], [], emu).
diff --git a/erts/test/install_SUITE.erl b/erts/test/install_SUITE.erl
index d6c6d6f30e..324b398caa 100644
--- a/erts/test/install_SUITE.erl
+++ b/erts/test/install_SUITE.erl
@@ -580,7 +580,7 @@ end_per_testcase(_Case, _Config) ->
     ok.
 
 make_dirs(Root, Suffix) ->
-    do_make_dirs(Root, string:tokens(Suffix, [$/])).
+    do_make_dirs(Root, string:lexemes(Suffix, [$/])).
 
 do_make_dirs(_Root, []) ->
     "";
@@ -709,4 +709,4 @@ join("") ->
 join([""|Ds]) ->
     join(Ds);
 join([D|Ds]) ->
-    "/" ++ string:strip(D, both, $/) ++ join(Ds).
+    "/" ++ string:trim(D, both, [$/]) ++ join(Ds).
diff --git a/erts/test/nt_SUITE.erl b/erts/test/nt_SUITE.erl
index 624e5484ba..3081b58835 100644
--- a/erts/test/nt_SUITE.erl
+++ b/erts/test/nt_SUITE.erl
@@ -117,7 +117,7 @@ wait_for_node(Name) ->
     do_wait_for_it(FullName,30).
 
 make_full_name(Name) ->
-    [_,Suffix] = string:tokens(atom_to_list(node()),"@"),
+    [_,Suffix] = string:lexemes(atom_to_list(node()),"@"),
     list_to_atom(Name ++ "@" ++ Suffix).
 
 
@@ -171,7 +171,7 @@ service_env(Config) when is_list(Config) ->
                     ["ERLSRV_SERVICE_NAME"]),
     "erlsrv.exe" = filename:basename(
                      hd(
-                       string:tokens(
+                       string:lexemes(
                          rpc:call(make_full_name(Name),
                                   os,
                                   getenv,
diff --git a/erts/test/otp_SUITE.erl b/erts/test/otp_SUITE.erl
index 54fcfd935f..3abe45c141 100644
--- a/erts/test/otp_SUITE.erl
+++ b/erts/test/otp_SUITE.erl
@@ -336,7 +336,7 @@ not_recommended_calls(Config, Apps0, MFA) ->
                 _ ->
                     AppStrings = [atom_to_list(A) || A <- SkippedApps],
                     Mess = io_lib:format("Application(s) not present: ~s\n",
-                                         [string:join(AppStrings, ", ")]),
+                                         [lists:join(", ", AppStrings)]),
                     {comment, Mess}
             end;
         _ ->
@@ -463,7 +463,7 @@ runtime_dependencies(Config) ->
 have_rdep(_App, [], _Dep) ->
     false;
 have_rdep(App, [RDep | RDeps], Dep) ->		    
-    [AppStr, _VsnStr] = string:tokens(RDep, "-"),
+    [AppStr, _VsnStr] = string:lexemes(RDep, "-"),
     case Dep == list_to_atom(AppStr) of
         true ->
             io:format("~p -> ~s~n", [App, RDep]),
diff --git a/erts/test/run_erl_SUITE.erl b/erts/test/run_erl_SUITE.erl
index fe1ccba1e2..08edd930b4 100644
--- a/erts/test/run_erl_SUITE.erl
+++ b/erts/test/run_erl_SUITE.erl
@@ -255,7 +255,7 @@ do_run_erl(Config, Case, Opt) ->
     
     net_kernel:monitor_nodes(true),
     open_port({spawn,Cmd}, []),
-    [_,Host] = string:tokens(atom_to_list(node()), "@"),
+    [_,Host] = string:lexemes(atom_to_list(node()), "@"),
     Node = list_to_atom(NodeName++"@"++Host),
 
     receive
diff --git a/erts/test/upgrade_SUITE.erl b/erts/test/upgrade_SUITE.erl
index a5639d927d..31ceb06314 100644
--- a/erts/test/upgrade_SUITE.erl
+++ b/erts/test/upgrade_SUITE.erl
@@ -287,7 +287,7 @@ create_relfile(Node,CreateDir,RelName0,RelVsn) ->
 			 true ->
 			     case filename:split(Path) -- SplitLibDir of
 				 [AppVsn,"ebin"] ->
-				     case string:tokens(AppVsn,"-") of
+				     case string:lexemes(AppVsn,"-") of
 					 [AppStr,Vsn] ->
 					     App = list_to_atom(AppStr),
 					     case lists:member(App,Exclude) of
diff --git a/erts/test/z_SUITE.erl b/erts/test/z_SUITE.erl
index d474c71c4f..cd7a894eb5 100644
--- a/erts/test/z_SUITE.erl
+++ b/erts/test/z_SUITE.erl
@@ -132,22 +132,9 @@ core_search_conf(RunByTS, DBTop, XDir) ->
 
 file_inspect(#core_search_conf{file = File}, Core) ->
     FRes0 = os:cmd(File ++ " " ++ Core),
-    FRes = case string:str(FRes0, Core) of
-	       0 ->
-		   FRes0;
-	       S ->
-		   L = length(FRes0),
-		   E = length(Core),
-		   case S of
-		       1 ->
-			   lists:sublist(FRes0, E+1, L+1);
-		       _ ->
-			   lists:sublist(FRes0, 1, S-1)
-			       ++
-			       " "
-			       ++
-			       lists:sublist(FRes0, E+1, L+1)
-		   end
+    FRes = case string:split(FRes0, Core) of
+	       [S1] -> S1;
+	       [S1,S2] -> lists:flatten(S1 ++ " " ++ S2)
 	   end,
     case re:run(FRes, "text|ascii", [caseless,{capture,none}]) of
 	match ->
@@ -194,9 +181,6 @@ mod_time_list(F) ->
 	    [0,0,0,0,0,0]
     end.
 
-str_strip(S) ->
-    string:strip(string:strip(string:strip(S), both, $\n), both, $\r).
-
 dump_core(#core_search_conf{ cerl = false }, _) ->
     ok;
 dump_core(_, {ignore, _Core}) ->
@@ -232,7 +216,7 @@ format_core(#core_search_conf{file = false}, Core, Ignore) ->
     io:format("  ~s~s " ++ time_fstr() ++ "~s~n",
 	      [Ignore, Core] ++ mod_time_list(Core));
 format_core(#core_search_conf{file = File}, Core, Ignore) ->
-    FRes = str_strip(os:cmd(File ++ " " ++ Core)),
+    FRes = string:trim(os:cmd(File ++ " " ++ Core)),
     case catch re:run(FRes, Core, [caseless,{capture,none}]) of
 	match ->
 	    io:format("  ~s~s " ++ time_fstr() ++ "~n",
diff --git a/lib/asn1/src/asn1ct_check.erl b/lib/asn1/src/asn1ct_check.erl
index 83d12600b7..321980e5e4 100644
--- a/lib/asn1/src/asn1ct_check.erl
+++ b/lib/asn1/src/asn1ct_check.erl
@@ -1576,13 +1576,15 @@ printable_string_1(#'Externalvaluereference'{value=Type}) ->
 printable_string_1({Atom,Line}) when is_atom(Atom), is_integer(Line) ->
     q(Atom);
 printable_string_1({object,definedsyntax,L}) ->
-    q(string:join([printable_string_1(Item) || Item <- L], " "));
+    Str = lists:join($\s, [printable_string_1(Item) || Item <- L]),
+    q(lists:flatten(Str));
 printable_string_1([_|_]=Def) ->
     case lists:all(fun is_integer/1, Def) of
 	true ->
 	    lists:flatten(io_lib:format("~p", [Def]));
 	false ->
-	    q(string:join([printable_string_1(Item) || Item <- Def], " "))
+            Str = lists:join($\s, [printable_string_1(Item) || Item <- Def]),
+            q(lists:flatten(Str))
     end;
 printable_string_1(Def) ->
     lists:flatten(io_lib:format("~p", [Def])).
diff --git a/lib/asn1/src/asn1ct_gen.erl b/lib/asn1/src/asn1ct_gen.erl
index 806f8420ec..84c7f39d55 100644
--- a/lib/asn1/src/asn1ct_gen.erl
+++ b/lib/asn1/src/asn1ct_gen.erl
@@ -796,7 +796,7 @@ result_line(NoOkWrapper, Items) ->
 result_line_1([SingleItem]) ->
     SingleItem;
 result_line_1(Items) ->
-    ["{",string:join(Items, ","),"}"].
+    ["{",lists:join(",",Items),"}"].
 
 try_catch() ->
     ["  catch",nl,
@@ -943,7 +943,7 @@ open_hrl(OutFile,Module) ->
 
 hrl_protector(OutFile) ->
     BaseName = filename:basename(OutFile),
-    P = "_" ++ string:to_upper(BaseName) ++ "_HRL_",
+    P = "_" ++ string:uppercase(BaseName) ++ "_HRL_",
     [if
 	 $A =< C, C =< $Z -> C;
 	 $a =< C, C =< $a -> C;
diff --git a/lib/asn1/src/asn1rtt_real_common.erl b/lib/asn1/src/asn1rtt_real_common.erl
index 3a79209015..81c1f54d74 100644
--- a/lib/asn1/src/asn1rtt_real_common.erl
+++ b/lib/asn1/src/asn1rtt_real_common.erl
@@ -125,7 +125,7 @@ encode_real(_C, {_,Base,_}) ->
 encode_real(C, Real) when is_list(Real) ->
     %% The Real string may come in as a NR1, NR2 or NR3 string.
     {Mantissa, Exponent} =
-	case string:tokens(Real,"Ee") of
+	case string:lexemes(Real,"Ee") of
 	    [NR2] ->
 		{NR2,0};
 	    [NR3MB,NR3E] ->
@@ -144,7 +144,7 @@ encode_real(C, Real) when is_list(Real) ->
 		NewMan = remove_trailing_zeros(Dec),
 		{NewMan,length(ZeroDecimal(NewMan))};
 	    _ ->
-		case string:tokens(Mantissa,",.") of
+		case string:lexemes(Mantissa,",.") of
 		    [Num] -> %% No decimal-mark
 			{integer_to_list(list_to_integer(Num)),0};
 		    [Num,Dec] ->
diff --git a/lib/common_test/src/ct.erl b/lib/common_test/src/ct.erl
index a12c0c9101..875301a8b2 100644
--- a/lib/common_test/src/ct.erl
+++ b/lib/common_test/src/ct.erl
@@ -1030,7 +1030,7 @@ make_and_load(Dir, Suite) ->
     EnvInclude =
 	case os:getenv("CT_INCLUDE_PATH") of
 	    false -> [];
-	    CtInclPath -> string:tokens(CtInclPath, [$:,$ ,$,])
+	    CtInclPath -> string:lexemes(CtInclPath, [$:,$ ,$,])
 	end,
     StartInclude =
 	case init:get_argument(include) of
diff --git a/lib/common_test/src/ct_config.erl b/lib/common_test/src/ct_config.erl
index d48ae830bb..b3f983dd46 100644
--- a/lib/common_test/src/ct_config.erl
+++ b/lib/common_test/src/ct_config.erl
@@ -659,7 +659,7 @@ decrypt_config_file(EncryptFileName, TargetFileName, {key,Key}) ->
 get_crypt_key_from_file(File) ->
     case file:read_file(File) of
 	{ok,Bin} ->
-	    case catch string:tokens(binary_to_list(Bin), [$\n,$\r]) of
+	    case catch string:lexemes(binary_to_list(Bin), [$\n,$\r]) of
 		[Key] ->
 		    Key;
 		_ ->
@@ -693,7 +693,7 @@ get_crypt_key_from_file() ->
 	noent ->
 	    Result;
 	_ ->
-	    case catch string:tokens(binary_to_list(Result), [$\n,$\r]) of
+	    case catch string:lexemes(binary_to_list(Result), [$\n,$\r]) of
 		[Key] ->
 		    io:format("~nCrypt key file: ~ts~n", [FullName]),
 		    Key;
diff --git a/lib/common_test/src/ct_config_plain.erl b/lib/common_test/src/ct_config_plain.erl
index e72b55971b..e77381d7cf 100644
--- a/lib/common_test/src/ct_config_plain.erl
+++ b/lib/common_test/src/ct_config_plain.erl
@@ -106,7 +106,7 @@ read_config_terms1({done,{eof,EL},_}, L, _, _) ->
 read_config_terms1({done,{error,Info,EL},_}, L, _, _) ->
     {error,{Info,{L,EL}}};
 read_config_terms1({more,_}, L, Terms, Rest) ->
-    case string:tokens(Rest, [$\n,$\r,$\t]) of
+    case string:lexemes(Rest, [$\n,$\r,$\t]) of
 	[] ->
 	    lists:reverse(Terms);
 	_ ->
diff --git a/lib/common_test/src/ct_conn_log_h.erl b/lib/common_test/src/ct_conn_log_h.erl
index cf0a228e1b..3e83020f45 100644
--- a/lib/common_test/src/ct_conn_log_h.erl
+++ b/lib/common_test/src/ct_conn_log_h.erl
@@ -224,7 +224,7 @@ now_to_time({_,_,MicroS}=Now) ->
     {calendar:now_to_local_time(Now),MicroS}.
 
 pretty_head({{{Y,Mo,D},{H,Mi,S}},MicroS},ConnMod,Text0) ->
-    Text = string:to_upper(atom_to_list(ConnMod) ++ Text0),
+    Text = string:uppercase(atom_to_list(ConnMod) ++ Text0),
     io_lib:format("= ~s ==== ~s-~s-~w::~s:~s:~s,~s ",
 		  [Text,t(D),month(Mo),Y,t(H),t(Mi),t(S),
 		   micro2milli(MicroS)]).
@@ -275,7 +275,7 @@ pad0(N,Str) ->
     lists:duplicate(N-M,$0) ++ Str.
 
 pad_char_end(N,Str,Char) ->
-    case length(lists:flatten(Str)) of
+    case string:length(Str) of
 	M when M<N -> Str ++ lists:duplicate(N-M,Char);
 	_ -> Str
     end.
diff --git a/lib/common_test/src/ct_framework.erl b/lib/common_test/src/ct_framework.erl
index 6066470233..7f7e9ae6f9 100644
--- a/lib/common_test/src/ct_framework.erl
+++ b/lib/common_test/src/ct_framework.erl
@@ -921,9 +921,10 @@ error_notification(Mod,Func,_Args,{Error,Loc}) ->
 	      end,
     ErrorStr = case ErrorSpec of
 		 {badmatch,Descr} ->
-		     Descr1 = lists:flatten(io_lib:format("~tP",[Descr,10])),
-		     if length(Descr1) > 50 ->
-			     Descr2 = string:substr(Descr1,1,50),
+                     Descr1 = io_lib:format("~tP",[Descr,10]),
+                     DescrLength = string:length(Descr1),
+                     if DescrLength > 50 ->
+			     Descr2 = string:slice(Descr1,0,50),
 			     io_lib:format("{badmatch,~ts...}",[Descr2]);
 			true ->
 			     io_lib:format("{badmatch,~ts}",[Descr1])
diff --git a/lib/common_test/src/ct_ftp.erl b/lib/common_test/src/ct_ftp.erl
index 8effb06e7e..ee4a6a6c45 100644
--- a/lib/common_test/src/ct_ftp.erl
+++ b/lib/common_test/src/ct_ftp.erl
@@ -285,7 +285,7 @@ init(KeyOrName,{IP,Port},{Username,Password}) ->
 	{ok,FtpPid} ->
 	    log(heading(init,KeyOrName), 
 		"Opened ftp connection:\nIP: ~tp\nUsername: ~tp\nPassword: ~p\n",
-		[IP,Username,lists:duplicate(length(Password),$*)]),
+		[IP,Username,lists:duplicate(string:length(Password),$*)]),
 	    {ok,FtpPid,#state{ftp_pid=FtpPid,target_name=KeyOrName}};
 	Error ->
 	    Error
diff --git a/lib/common_test/src/ct_logs.erl b/lib/common_test/src/ct_logs.erl
index ba7660fe6a..028c265420 100644
--- a/lib/common_test/src/ct_logs.erl
+++ b/lib/common_test/src/ct_logs.erl
@@ -1188,26 +1188,23 @@ print_style(Fd, IoFormat, StyleSheet) ->
     case file:read_file(StyleSheet) of
 	{ok,Bin} ->
 	    Str = b2s(Bin,encoding(StyleSheet)),
-	    Pos0 = case string:str(Str,"<style>") of
-		       0 -> string:str(Str,"<STYLE>");
-		       N0 -> N0
-		   end,
-	    Pos1 = case string:str(Str,"</style>") of
-		       0 -> string:str(Str,"</STYLE>");
-		       N1 -> N1
-		   end,
-	    if (Pos0 == 0) and (Pos1 /= 0) ->
-		    print_style_error(Fd, IoFormat,
-				      StyleSheet, missing_style_start_tag);
-	       (Pos0 /= 0) and (Pos1 == 0) ->
-		    print_style_error(Fd, IoFormat,
-				      StyleSheet,missing_style_end_tag);
-	       Pos0 /= 0 ->
-		    Style = string:sub_string(Str,Pos0,Pos1+7),
-		    IoFormat(Fd,"~ts\n",[Style]);
-	       Pos0 == 0 ->
-		    IoFormat(Fd,"<style>\n~ts</style>\n",[Str])
-	    end;
+            case re:run(Str,"<style>.*</style>",
+                        [dotall,caseless,{capture,all,list}]) of
+                nomatch ->
+                    case re:run(Str,"</?style>",[caseless,{capture,all,list}]) of
+                        nomatch ->
+                            IoFormat(Fd,"<style>\n~ts</style>\n",[Str]);
+                        {match,["</"++_]} ->
+                            print_style_error(Fd, IoFormat,
+                                              StyleSheet,
+                                              missing_style_start_tag);
+                        {match,[_]} ->
+                            print_style_error(Fd, IoFormat,
+                                              StyleSheet,missing_style_end_tag)
+                    end;
+                {match,[Style]} ->
+                    IoFormat(Fd,"~ts\n",[Style])
+            end;
 	{error,Reason} ->
 	    print_style_error(Fd,IoFormat,StyleSheet,Reason)
     end.
@@ -1414,9 +1411,9 @@ make_one_index_entry1(SuiteName, Link, Label, Success, Fail, UserSkip, AutoSkip,
     {Lbl,Timestamp,Node,AllInfo} =
 	case All of
 	    {true,OldRuns} -> 
-		[_Prefix,NodeOrDate|_] = string:tokens(Link,"."),
-		Node1 = case string:chr(NodeOrDate,$@) of
-			    0 -> "-";
+		[_Prefix,NodeOrDate|_] = string:lexemes(Link,"."),
+		Node1 = case string:find(NodeOrDate,[$@]) of
+			    nomatch -> "-";
 			    _ -> NodeOrDate
 			end,
 
@@ -1523,7 +1520,7 @@ not_built(BaseName,_LogDir,_All,Missing) ->
     %%            Top.ObjDir | Top.ObjDir.suites | Top.ObjDir.Suite | 
     %%            Top.ObjDir.Suite.cases | Top.ObjDir.Suite.Case    
     Failed =
-	case string:tokens(BaseName,".") of
+	case string:lexemes(BaseName,".") of
 	    [T,O] when is_list(T) ->		% all under Top.ObjDir
 		locate_info({T,O},all,Missing);
 	    [T,O,"suites"] ->
@@ -2051,9 +2048,9 @@ sort_all_runs(Dirs) ->
     %% "YYYY-MM-DD_HH.MM.SS"
     lists:sort(fun(Dir1,Dir2) ->
 		       [SS1,MM1,HH1,Date1|_] =
-			   lists:reverse(string:tokens(Dir1,[$.,$_])),
+			   lists:reverse(string:lexemes(Dir1,[$.,$_])),
 		       [SS2,MM2,HH2,Date2|_] =
-			   lists:reverse(string:tokens(Dir2,[$.,$_])),
+			   lists:reverse(string:lexemes(Dir2,[$.,$_])),
 		       {Date1,HH1,MM1,SS1} > {Date2,HH2,MM2,SS2}
 	       end, Dirs).
 
@@ -2063,9 +2060,9 @@ sort_ct_runs(Dirs) ->
     lists:sort(
       fun(Dir1,Dir2) ->
 	      [SS1,MM1,DateHH1 | _] =
-		  lists:reverse(string:tokens(filename:dirname(Dir1),[$.])),
+		  lists:reverse(string:lexemes(filename:dirname(Dir1),[$.])),
 	      [SS2,MM2,DateHH2 | _] =
-		  lists:reverse(string:tokens(filename:dirname(Dir2),[$.])),
+		  lists:reverse(string:lexemes(filename:dirname(Dir2),[$.])),
 	      {DateHH1,MM1,SS1} =< {DateHH2,MM2,SS2}
       end, Dirs).
 
@@ -2211,27 +2208,15 @@ runentry(Dir, Totals={Node,Label,Logs,
 		    0 -> "-";
 		    N -> integer_to_list(N)
 		end,
-    StripExt = 
-	fun(File) ->
-		string:sub_string(File,1,
-				  length(File)-
-				      length(?logdir_ext)) ++ ", "
-	end,
-    Polish =  fun(S) -> case lists:reverse(S) of
-			    [32,$,|Rev] -> lists:reverse(Rev);
-			    [$,|Rev] -> lists:reverse(Rev);
-			    _ -> S
-			end 
-	      end,
-    TestNames = Polish(lists:flatten(lists:map(StripExt,Logs))),
+
+    RootNames = lists:map(fun(F) -> filename:rootname(F,?logdir_ext) end, Logs),
+    TestNames = lists:flatten(lists:join(", ", RootNames)),
     TestNamesTrunc =
-	if TestNames=="" -> 
-		"";
-	   length(TestNames) < ?testname_width ->
+	if length(TestNames) < ?testname_width ->
 		TestNames;
 	   true ->
-		Trunc = Polish(string:substr(TestNames,1,
-					     ?testname_width-3)),
+		Trunc = string:trim(string:slice(TestNames,0,?testname_width-3),
+                                    trailing,",\s"),
 		lists:flatten(io_lib:format("~ts...",[Trunc]))
 	end,
     TotMissingStr =
@@ -2374,7 +2359,7 @@ force_rename(From,To,Number) ->
 
 
 timestamp(Dir) ->
-    TsR = lists:reverse(string:tokens(Dir,".-_")),
+    TsR = lists:reverse(string:lexemes(Dir,".-_")),
     [S,Min,H,D,M,Y] = [list_to_integer(N) || N <- lists:sublist(TsR,6)],
     format_time({{Y,M,D},{H,Min,S}}).
 
@@ -2923,7 +2908,7 @@ cache_vsn() ->
 	    VSNfile = filename:join([EbinDir,"..","vsn.mk"]),
 	    case file:read_file(VSNfile) of
 		{ok,Bin} ->
-		    [_,VSN] = string:tokens(binary_to_list(Bin),[$=,$\n,$ ]),
+		    [_,VSN] = string:lexemes(binary_to_list(Bin),[$=,$\n,$ ]),
 		    VSN;
 		_ ->
 		    undefined
@@ -3320,7 +3305,7 @@ insert_javascript({tablesorter,TableName,
 			  end, [{"CTDateSorter",DateCols},
 				{"CTTextSorter",TextCols},
 				{"CTValSorter",ValCols}]))),
-    Headers1 = string:substr(Headers, 1, length(Headers)-2),
+    Headers1 = string:trim(Headers, trailing, ",\n"),
 
     ["<script type=\"text/javascript\">\n",
      "// Parser for date format, e.g: Wed Jul 4 2012 11:24:15\n",
diff --git a/lib/common_test/src/ct_master.erl b/lib/common_test/src/ct_master.erl
index 6e6d1879c2..44d3fb8f64 100644
--- a/lib/common_test/src/ct_master.erl
+++ b/lib/common_test/src/ct_master.erl
@@ -807,7 +807,7 @@ filter_accessible(InitOptions, Inaccessible)->
 
 start_nodes(InitOptions)->
     lists:foreach(fun({NodeName, Options})->
-	[NodeS,HostS]=string:tokens(atom_to_list(NodeName), "@"),
+	[NodeS,HostS]=string:lexemes(atom_to_list(NodeName), "@"),
 	Node=list_to_atom(NodeS),
 	Host=list_to_atom(HostS),
 	HasNodeStart = lists:keymember(node_start, 1, Options),
diff --git a/lib/common_test/src/ct_master_logs.erl b/lib/common_test/src/ct_master_logs.erl
index d8ecd641ed..fd92f73f63 100644
--- a/lib/common_test/src/ct_master_logs.erl
+++ b/lib/common_test/src/ct_master_logs.erl
@@ -297,7 +297,7 @@ sort_all_runs(Dirs) ->
     %% "YYYY-MM-DD_HH.MM.SS"
     KeyList =
 	lists:map(fun(Dir) ->
-			  case lists:reverse(string:tokens(Dir,[$.,$_])) of
+			  case lists:reverse(string:lexemes(Dir,[$.,$_])) of
 			      [SS,MM,HH,Date|_] ->
 				  {{Date,HH,MM,SS},Dir};
 			      _Other ->
@@ -312,18 +312,8 @@ runentry(Dir) ->
     {MasterStr,NodesStr} = 
 	case read_details_file(Dir) of
 	    {Master,Nodes} when is_list(Nodes) ->
-		[_,Host] = string:tokens(atom_to_list(Master),"@"),
-		NodesList = 
-		    lists:reverse(lists:map(fun(N) ->
-						    atom_to_list(N) ++ ", "
-					    end,Nodes)),
-		case NodesList of
-		    [N|NListR] ->
-			N1 = string:sub_string(N,1,length(N)-2),
-			{Host,lists:flatten(lists:reverse([N1|NListR]))};
-		    [] ->
-			{Host,""}
-		end;
+		[_,Host] = string:lexemes(atom_to_list(Master),"@"),
+                {Host,lists:concat(lists:join(", ",Nodes))};
 	    _Error ->
 		{"unknown",""}
 	end,
@@ -348,7 +338,7 @@ all_runs_header() ->
       xhtml("", "</tr></thead>\n<tbody>\n")]].
 
 timestamp(Dir) ->
-    [S,Min,H,D,M,Y|_] = lists:reverse(string:tokens(Dir,".-_")),
+    [S,Min,H,D,M,Y|_] = lists:reverse(string:lexemes(Dir,".-_")),
     [S1,Min1,H1,D1,M1,Y1] = [list_to_integer(N) || N <- [S,Min,H,D,M,Y]],
     format_time({{Y1,M1,D1},{H1,Min1,S1}}).
 
diff --git a/lib/common_test/src/ct_netconfc.erl b/lib/common_test/src/ct_netconfc.erl
index 2c4b97df20..29188a648e 100644
--- a/lib/common_test/src/ct_netconfc.erl
+++ b/lib/common_test/src/ct_netconfc.erl
@@ -1467,7 +1467,7 @@ decode_data(Other) ->
     {error,{unexpected_rpc_reply,Other}}.
 
 get_qualified_name(Tag) ->
-    case string:tokens(atom_to_list(Tag),":") of
+    case string:lexemes(atom_to_list(Tag),":") of
 	[TagStr] -> {[],TagStr};
 	[PrefixStr,TagStr] -> {PrefixStr,TagStr}
     end.
diff --git a/lib/common_test/src/ct_release_test.erl b/lib/common_test/src/ct_release_test.erl
index 551a7e06d7..4af9afb45b 100644
--- a/lib/common_test/src/ct_release_test.erl
+++ b/lib/common_test/src/ct_release_test.erl
@@ -817,7 +817,7 @@ get_runtime_deps([App|Apps],StartApps,Acc,Visited) ->
 	    RuntimeDeps =
 		lists:flatmap(
 		  fun(Str) ->
-			  [RuntimeAppStr,_] = string:tokens(Str,"-"),
+			  [RuntimeAppStr,_] = string:lexemes(Str,"-"),
 			  RuntimeApp = list_to_atom(RuntimeAppStr),
 			  case {lists:keymember(RuntimeApp,1,Acc),
 				lists:member(RuntimeApp,StartApps)} of
diff --git a/lib/common_test/src/ct_run.erl b/lib/common_test/src/ct_run.erl
index 14f28f9ca3..9436236719 100644
--- a/lib/common_test/src/ct_run.erl
+++ b/lib/common_test/src/ct_run.erl
@@ -147,7 +147,7 @@ script_start(Args) ->
 	    CTVsn =
 		case filename:basename(code:lib_dir(common_test)) of
 		    CTBase when is_list(CTBase) ->
-			case string:tokens(CTBase, "-") of
+			case string:lexemes(CTBase, "-") of
 			    ["common_test",Vsn] -> " v"++Vsn;
 			    _ -> ""
 			end
@@ -315,7 +315,7 @@ script_start1(Parent, Args) ->
 			{undefined,InclDirs};
 		    CtInclPath ->
 			AllInclDirs =
-			    string:tokens(CtInclPath,[$:,$ ,$,]) ++ InclDirs,
+			    string:lexemes(CtInclPath,[$:,$ ,$,]) ++ InclDirs,
 			application:set_env(common_test, include, AllInclDirs),
 			{undefined,AllInclDirs}
 		end;
@@ -1096,7 +1096,7 @@ run_test2(StartOpts) ->
 			application:set_env(common_test, include, InclDirs),
 			{undefined,InclDirs};
 		    CtInclPath ->
-			InclDirs1 = string:tokens(CtInclPath, [$:,$ ,$,]),
+			InclDirs1 = string:lexemes(CtInclPath, [$:,$ ,$,]),
 			AllInclDirs = InclDirs1++InclDirs,
 			application:set_env(common_test, include, AllInclDirs),
 			{undefined,AllInclDirs}
@@ -1482,7 +1482,7 @@ run_testspec2(TestSpec) ->
 		    false ->
 			Opts#opts.include;
 		    CtInclPath ->
-			EnvInclude = string:tokens(CtInclPath, [$:,$ ,$,]),
+			EnvInclude = string:lexemes(CtInclPath, [$:,$ ,$,]),
 			EnvInclude++Opts#opts.include
 		end,
 	    application:set_env(common_test, include, AllInclude),
diff --git a/lib/common_test/src/ct_ssh.erl b/lib/common_test/src/ct_ssh.erl
index ca62357e1c..491d56dfc1 100644
--- a/lib/common_test/src/ct_ssh.erl
+++ b/lib/common_test/src/ct_ssh.erl
@@ -996,7 +996,8 @@ init(KeyOrName, {ConnType,Addr,Port}, AllOpts) ->
 	    try_log(heading(init,KeyOrName), 
 		    "Opened ~w connection:\n"
 		    "Host: ~tp (~p)\nUser: ~tp\nPassword: ~p\n",
-		[ConnType,Addr,Port,User,lists:duplicate(length(Password),$*)]),
+		[ConnType,Addr,Port,User,
+                 lists:duplicate(string:length(Password),$*)]),
 	    {ok,SSHRef,#state{ssh_ref=SSHRef, conn_type=ConnType,
 			      target=KeyOrName}}
     end.
diff --git a/lib/common_test/src/ct_util.erl b/lib/common_test/src/ct_util.erl
index abf131f4df..3c0fead5b2 100644
--- a/lib/common_test/src/ct_util.erl
+++ b/lib/common_test/src/ct_util.erl
@@ -795,25 +795,25 @@ parse_table(Data) ->
     {Heading,Lines}.
 
 get_headings(["|" ++ Headings | Rest]) ->
-    {remove_space(string:tokens(Headings, "|"),[]), Rest};
+    {remove_space(string:lexemes(Headings, "|"),[]), Rest};
 get_headings([_ | Rest]) ->
     get_headings(Rest);
 get_headings([]) ->
     {{},[]}.
 
 parse_row(["|" ++ _ = Row | T], Rows, NumCols) when NumCols > 1 ->
-    case string:tokens(Row, "|") of
+    case string:lexemes(Row, "|") of
 	Values when length(Values) =:= NumCols ->
 	    parse_row(T,[remove_space(Values,[])|Rows], NumCols);
 	Values when length(Values) < NumCols ->
 	    parse_row([Row ++"\n"++ hd(T) | tl(T)], Rows, NumCols)
     end;
-parse_row(["|" ++ _ = Row | T], Rows, 1 = NumCols) ->
-    case string:rchr(Row, $|) of
-	1 ->
+parse_row(["|" ++ X = Row | T], Rows, 1 = NumCols) ->
+    case string:find(X, [$|]) of
+	nomatch ->
 	    parse_row([Row ++"\n"++hd(T) | tl(T)], Rows, NumCols);
 	_Else ->
-	    parse_row(T, [remove_space(string:tokens(Row,"|"),[])|Rows],
+	    parse_row(T, [remove_space(string:lexemes(Row,"|"),[])|Rows],
 		      NumCols)
     end;
 parse_row([_Skip | T], Rows, NumCols) ->
@@ -822,7 +822,7 @@ parse_row([], Rows, _NumCols) ->
     lists:reverse(Rows).
 
 remove_space([Str|Rest],Acc) ->
-    remove_space(Rest,[string:strip(string:strip(Str),both,$')|Acc]);
+    remove_space(Rest,[string:trim(string:trim(Str,both,[$\s]),both,[$'])|Acc]);
 remove_space([],Acc) ->
     list_to_tuple(lists:reverse(Acc)).
 
@@ -832,7 +832,7 @@ remove_space([],Acc) ->
 %%%
 %%% @doc
 is_test_dir(Dir) ->
-    lists:last(string:tokens(filename:basename(Dir), "_")) == "test".
+    lists:last(string:lexemes(filename:basename(Dir), "_")) == "test".
 
 %%%-----------------------------------------------------------------
 %%% @spec 
@@ -1077,7 +1077,7 @@ open_url(iexplore, Args, URL) ->
     _ = case win32reg:values(R) of
 	{ok, Paths} ->
 	    Path = proplists:get_value(default, Paths),
-	    [Cmd | _] = string:tokens(Path, "%"),
+	    [Cmd | _] = string:lexemes(Path, "%"),
 	    Cmd1 = Cmd ++ " " ++ Args ++ " " ++ URL,
 	    io:format(?def_gl, "~nOpening ~ts with command:~n  ~ts~n", [URL,Cmd1]),
 	    open_port({spawn,Cmd1}, []);
diff --git a/lib/common_test/src/cth_surefire.erl b/lib/common_test/src/cth_surefire.erl
index da68bd105e..4407ff56c1 100644
--- a/lib/common_test/src/cth_surefire.erl
+++ b/lib/common_test/src/cth_surefire.erl
@@ -184,15 +184,14 @@ end_tc(Name, _Config, _Res, State = #state{ curr_suite = Suite,
     Log =
 	case Log0 of
 	    "" ->
-		LowerSuiteName = string:to_lower(atom_to_list(Suite)),
+		LowerSuiteName = string:lowercase(atom_to_list(Suite)),
 		filename:join(CurrLogDir,LowerSuiteName++"."++Name++".html");
 	    _ ->
 		Log0
 	end,
     Url = make_url(UrlBase,Log),
     ClassName = atom_to_list(Suite),
-    PGroup = string:join([ atom_to_list(Group)||
-			     Group <- lists:reverse(Groups)],"."),
+    PGroup = lists:concat(lists:join(".",lists:reverse(Groups))),
     TimeTakes = io_lib:format("~f",[timer:now_diff(?now,TS) / 1000000]),
     State#state{ test_cases = [#testcase{ log = Log,
 					  url = Url,
@@ -317,9 +316,9 @@ make_url(undefined,_) ->
 make_url(_,[]) ->
     undefined;
 make_url(UrlBase0,Log) ->
-    UrlBase = string:strip(UrlBase0,right,$/),
+    UrlBase = string:trim(UrlBase0,trailing,[$/]),
     RelativeLog = get_relative_log_url(Log),
-    string:join([UrlBase,RelativeLog],"/").
+    lists:flatten(lists:join($/,[UrlBase,RelativeLog])).
 
 get_test_root(Log) ->
     LogParts = filename:split(Log),
@@ -329,7 +328,7 @@ get_relative_log_url(Log) ->
     LogParts = filename:split(Log),
     Start = length(LogParts)-?log_depth,
     Length = ?log_depth+1,
-    string:join(lists:sublist(LogParts,Start,Length),"/").
+    lists:flatten(lists:join($/,lists:sublist(LogParts,Start,Length))).
 
 count_tcs([#testcase{name=ConfCase}|TCs],Ok,F,S)
   when ConfCase=="init_per_suite";
diff --git a/lib/common_test/src/test_server.erl b/lib/common_test/src/test_server.erl
index dc6b7a536c..35a73e6d2e 100644
--- a/lib/common_test/src/test_server.erl
+++ b/lib/common_test/src/test_server.erl
@@ -462,11 +462,12 @@ run_test_case_msgloop(#st{ref=Ref,pid=Pid,end_conf_pid=EndConfPid0}=St0) ->
 			 %% it as a comment, potentially replacing user data
 			 Error = lists:flatten(io_lib:format("Aborted: ~tp",
 							     [Reason])),
-			 Error1 = lists:flatten([string:strip(S,left) ||
-						    S <- string:tokens(Error,
-								       [$\n])]),
-			 Comment = if length(Error1) > 63 ->
-					   string:substr(Error1,1,60) ++ "...";
+			 Error1 = lists:flatten([string:trim(S,leading,"\s") ||
+						    S <- string:lexemes(Error,
+                                                                        [$\n])]),
+                         ErrorLength = string:length(Error1),
+			 Comment = if ErrorLength > 63 ->
+					   string:slice(Error1,0,60) ++ "...";
 				      true ->
 					   Error1
 				   end,
@@ -2697,9 +2698,9 @@ is_cover() ->
 is_debug() ->
     case catch erlang:system_info(debug_compiled) of
 	{'EXIT', _} ->
-	    case string:str(erlang:system_info(system_version), "debug") of
-		Int when is_integer(Int), Int > 0 -> true;
-		_ -> false
+	    case string:find(erlang:system_info(system_version), "debug") of
+                nomatch -> false;
+		_ -> true
 	    end;
 	Res ->
 	    Res
@@ -2735,9 +2736,9 @@ has_superfluous_schedulers() ->
 %% We might want to do more tests on a commercial platform, for instance
 %% ensuring that all applications have documentation).
 is_commercial() ->
-    case string:str(erlang:system_info(system_version), "source") of
-	Int when is_integer(Int), Int > 0 -> false;
-	_ -> true
+    case string:find(erlang:system_info(system_version), "source") of
+        nomatch -> true;
+	_ -> false
     end.
 
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
diff --git a/lib/common_test/src/test_server_ctrl.erl b/lib/common_test/src/test_server_ctrl.erl
index 71978c7267..c70ea4ef9d 100644
--- a/lib/common_test/src/test_server_ctrl.erl
+++ b/lib/common_test/src/test_server_ctrl.erl
@@ -1464,13 +1464,14 @@ get_suites([], Mods) ->
     lists:reverse(Mods).
 
 add_mod(Mod, Mods) ->
-    case string:rstr(atom_to_list(Mod), "_SUITE") of
-	0 -> false;
-	_ ->					% test suite
+    case lists:reverse(atom_to_list(Mod)) of
+        "ETIUS_" ++ _ -> % test suite
 	     case lists:member(Mod, Mods) of
 		 true ->  false;
 		 false -> true
-	     end
+	     end;
+        _ ->
+            false
     end.
 
 
@@ -2611,7 +2612,7 @@ run_test_cases_loop([{conf,Ref,Props,{Mod,Func}}|_Cases]=Cs0,
 				NumStr ->
 				    %% Ex: "123 456 789" or "123,456,789" -> {123,456,789}
 				    list_to_tuple([list_to_integer(NS) ||
-						   NS <- string:tokens(NumStr, [$ ,$:,$,])])
+						   NS <- string:lexemes(NumStr, [$ ,$:,$,])])
 			    end,
 			{shuffle_cases(Ref, Cs0, UseSeed),{shuffle,UseSeed}}
 		end;
@@ -3979,11 +3980,12 @@ progress(skip, CaseNum, Mod, Func, GrName, Loc, Reason, Time,
 			       true -> "~w"
 			    end, [Time]),
     ReasonStr = escape_chars(reason_to_string(Reason1)),
-    ReasonStr1 = lists:flatten([string:strip(S,left) ||
-				S <- string:tokens(ReasonStr,[$\n])]),
+    ReasonStr1 = lists:flatten([string:trim(S,leading,"\s") ||
+				S <- string:lexemes(ReasonStr,[$\n])]),
+    ReasonLength = string:length(ReasonStr1),
     ReasonStr2 =
-	if length(ReasonStr1) > 80 ->
-		string:substr(ReasonStr1, 1, 77) ++ "...";
+	if ReasonLength > 80 ->
+		string:slice(ReasonStr1, 0, 77) ++ "...";
 	   true ->
 		ReasonStr1
 	end,
@@ -4067,11 +4069,12 @@ progress(failed, CaseNum, Mod, Func, GrName, unknown, Reason, Time,
 			       true -> "~w"
 			    end, [Time]),
     ErrorReason = escape_chars(lists:flatten(io_lib:format("~tp", [Reason]))),
-    ErrorReason1 = lists:flatten([string:strip(S,left) ||
-				  S <- string:tokens(ErrorReason,[$\n])]),
+    ErrorReason1 = lists:flatten([string:trim(S,leading,"\s") ||
+				  S <- string:lexemes(ErrorReason,[$\n])]),
+    ErrorReasonLength = string:length(ErrorReason1),
     ErrorReason2 =
-	if length(ErrorReason1) > 63 ->
-		string:substr(ErrorReason1, 1, 60) ++ "...";
+	if ErrorReasonLength > 63 ->
+		string:slice(ErrorReason1, 0, 60) ++ "...";
 	   true ->
 		ErrorReason1
 	end,
diff --git a/lib/common_test/src/test_server_node.erl b/lib/common_test/src/test_server_node.erl
index c0d7e12721..f0f9cea6e0 100644
--- a/lib/common_test/src/test_server_node.erl
+++ b/lib/common_test/src/test_server_node.erl
@@ -315,9 +315,11 @@ start_node_peer(SlaveName, OptList, From, TI) ->
     Prog0 = start_node_get_option_value(erl, OptList, default),
     Prog = quote_progname(pick_erl_program(Prog0)),
     Args = 
-	case string:str(SuppliedArgs,"-setcookie") of
-	    0 -> "-setcookie " ++ TI#target_info.cookie ++ " " ++ SuppliedArgs;
-	    _ -> SuppliedArgs
+	case string:find(SuppliedArgs,"-setcookie") of
+	    nomatch ->
+                "-setcookie " ++ TI#target_info.cookie ++ " " ++ SuppliedArgs;
+	    _ ->
+                SuppliedArgs
 	end,
     Cmd = lists:concat([Prog,
 			" -detached ",
@@ -612,7 +614,7 @@ pick_erl_program(L) ->
 %% emulator and flags as the test node. The return from lib:progname()
 %% could then typically be '/<full_path_to>/cerl -gcov').
 quote_progname(Progname) ->
-    do_quote_progname(string:tokens(Progname," ")).
+    do_quote_progname(string:lexemes(Progname," ")).
 
 do_quote_progname([Prog]) ->
     "\""++Prog++"\"";
diff --git a/lib/common_test/src/unix_telnet.erl b/lib/common_test/src/unix_telnet.erl
index 8ac467014c..5992f26e6d 100644
--- a/lib/common_test/src/unix_telnet.erl
+++ b/lib/common_test/src/unix_telnet.erl
@@ -121,7 +121,8 @@ connect1(Name,Ip,Port,Timeout,KeepAlive,TCPNoDelay,Username,Password) ->
 							  prompt,?prx,[]) of
 			    {ok,{prompt,?password},_} ->
 				ok = ct_telnet_client:send_data(Pid,Password),
-				Stars = lists:duplicate(length(Password),$*),
+				Stars =
+                                    lists:duplicate(string:length(Password),$*),
 				log(Name,send,"Password: ~s",[Stars]),
 %				ok = ct_telnet_client:send_data(Pid,""),
 				case ct_telnet:silent_teln_expect(Name,Pid,[],
diff --git a/lib/common_test/test/ct_config_SUITE.erl b/lib/common_test/test/ct_config_SUITE.erl
index 250700741c..5ffc735d6a 100644
--- a/lib/common_test/test/ct_config_SUITE.erl
+++ b/lib/common_test/test/ct_config_SUITE.erl
@@ -213,8 +213,8 @@ reformat_events(Events, EH) ->
 skip_dynamic() ->
     case os:getenv("TS_EXTRA_PLATFORM_LABEL") of
 	TSExtraPlatformLabel when is_list(TSExtraPlatformLabel) ->
-	    case string:str(TSExtraPlatformLabel,"TimeWarpingOS") of
-		0 -> false;
+	    case string:find(TSExtraPlatformLabel,"TimeWarpingOS") of
+		nomatch -> false;
 		_ -> true
 	    end;
 	_ ->
diff --git a/lib/common_test/test/ct_hooks_SUITE.erl b/lib/common_test/test/ct_hooks_SUITE.erl
index 8ba14e63bc..3c1e887f65 100644
--- a/lib/common_test/test/ct_hooks_SUITE.erl
+++ b/lib/common_test/test/ct_hooks_SUITE.erl
@@ -257,7 +257,7 @@ cth_log(Config) when is_list(Config) ->
     lists:foreach(
       fun(UnexpIoLog) ->
 	      {ok,Bin} = file:read_file(UnexpIoLog),
-	      Ts = string:tokens(binary_to_list(Bin),[$\n]),
+	      Ts = string:lexemes(binary_to_list(Bin),[$\n]),
 	      Matches = lists:foldl(fun([$=,$E,$R,$R,$O,$R|_],  N) ->
 					    N+1;
 				       ([$L,$o,$g,$g,$e,$r|_],  N) ->
diff --git a/lib/common_test/test/ct_log_SUITE.erl b/lib/common_test/test/ct_log_SUITE.erl
index 93affda398..9655b6f09a 100644
--- a/lib/common_test/test/ct_log_SUITE.erl
+++ b/lib/common_test/test/ct_log_SUITE.erl
@@ -174,7 +174,7 @@ verify(Config) ->
     TcLogFile = proplists:get_value(the_logfile, SavedCfg),
     Pid = proplists:get_value(the_pid, SavedCfg),
     StrPid = lists:flatten(io_lib:format("~p",[Pid])),
-    EscPid = "&lt;" ++ string:substr(StrPid, 2, length(StrPid)-2) ++ "&gt;", 
+    EscPid = "&lt;" ++ string:slice(StrPid, 1, length(StrPid)-2) ++ "&gt;", 
     String = proplists:get_value(the_string, SavedCfg),
     ct:log("Read from prev testcase: ~p & ~p", [TcLogFile,Pid]),
     {ok,Dev} = file:open(TcLogFile, [read]),
diff --git a/lib/common_test/test/ct_pre_post_test_io_SUITE.erl b/lib/common_test/test/ct_pre_post_test_io_SUITE.erl
index 7ffe6f045b..0b85392009 100644
--- a/lib/common_test/test/ct_pre_post_test_io_SUITE.erl
+++ b/lib/common_test/test/ct_pre_post_test_io_SUITE.erl
@@ -164,7 +164,7 @@ pre_post_io(Config) ->
       fun(PrePostIoFile) ->
 	      ct:log("Reading Pre/Post Test IO Log file: ~ts", [PrePostIoFile]),
 	      {ok,Bin} = file:read_file(PrePostIoFile),
-	      Ts = string:tokens(binary_to_list(Bin),[$\n]),
+	      Ts = string:lexemes(binary_to_list(Bin),[$\n]),
 	      PrePostIOEntries =
 		  lists:foldl(fun([$L,$o,$g,$g,$e,$r|_],
 				  {pre,PreLogN,PreErrN,0,0}) ->
@@ -203,7 +203,7 @@ pre_post_io(Config) ->
       fun(UnexpIoFile) ->
 	      ct:log("Reading Unexpected IO Log file: ~ts", [UnexpIoFile]),
 	      {ok,Bin} = file:read_file(UnexpIoFile),
-	      Ts = string:tokens(binary_to_list(Bin),[$\n]),
+	      Ts = string:lexemes(binary_to_list(Bin),[$\n]),
 	      UnexpIOEntries =
 		  lists:foldl(fun([$L,$o,$g,$g,$e,$r|_], [LogN,ErrN]) ->
 				      [LogN+1,ErrN];
diff --git a/lib/common_test/test/ct_priv_dir_SUITE_data/priv_dir_SUITE.erl b/lib/common_test/test/ct_priv_dir_SUITE_data/priv_dir_SUITE.erl
index 1b171801a3..b1d191873d 100644
--- a/lib/common_test/test/ct_priv_dir_SUITE_data/priv_dir_SUITE.erl
+++ b/lib/common_test/test/ct_priv_dir_SUITE_data/priv_dir_SUITE.erl
@@ -126,12 +126,12 @@ default(Config) ->
 
 auto_per_tc(Config) ->
     PrivDir = proplists:get_value(priv_dir, Config),
-    ["log_private",_] = string:tokens(filename:basename(PrivDir), "."),
+    ["log_private",_] = string:lexemes(filename:basename(PrivDir), "."),
     {ok,_} = file:list_dir(PrivDir).
 
 manual_per_tc(Config) ->
     PrivDir = proplists:get_value(priv_dir, Config),
-    ["log_private",_] = string:tokens(filename:basename(PrivDir), "."),
+    ["log_private",_] = string:lexemes(filename:basename(PrivDir), "."),
     {error,_} = file:list_dir(PrivDir),
     ok = ct:make_priv_dir(),
     {ok,_} = file:list_dir(PrivDir).
diff --git a/lib/common_test/test/ct_test_support.erl b/lib/common_test/test/ct_test_support.erl
index 44c27e54c2..2ba7c7c13f 100644
--- a/lib/common_test/test/ct_test_support.erl
+++ b/lib/common_test/test/ct_test_support.erl
@@ -88,7 +88,7 @@ start_slave(Config, Level) ->
     start_slave(ct, Config, Level).
 
 start_slave(NodeName, Config, Level) ->
-    [_,Host] = string:tokens(atom_to_list(node()), "@"),
+    [_,Host] = string:lexemes(atom_to_list(node()), "@"),
     test_server:format(0, "Trying to start ~s~n",
 		       [atom_to_list(NodeName)++"@"++Host]),
     PR = proplists:get_value(printable_range,Config,io:printable_range()),
@@ -1088,8 +1088,8 @@ locate({TEH,Name,{'DEF','RUNDIR'}}, Node, [Ev|Evs], Config) ->
 	{TEH,#event{name=Name, node=Node, data=EvData}} ->
 	    {_,{_,LogDir}} = lists:keysearch(logdir, 1, get_opts(Config)),
 	    D = filename:join(LogDir, "ct_run." ++ atom_to_list(Node)),
-	    case string:str(EvData, D) of
-		0 -> exit({badmatch,EvData});
+	    case string:find(EvData, D) of
+		nomatch -> exit({badmatch,EvData});
 		_ -> ok	    
 	    end,
 	    {Config,Evs};
@@ -1104,8 +1104,8 @@ locate({TEH,Name,{'DEF',{'START_TIME','LOGDIR'}}}, Node, [Ev|Evs], Config) ->
 		{DT={{_,_,_},{_,_,_}},Dir} when is_list(Dir) ->
 		    {_,{_,LogDir}} = lists:keysearch(logdir, 1, get_opts(Config)),
 		    D = filename:join(LogDir, "ct_run." ++ atom_to_list(Node)),
-		    case string:str(Dir, D) of
-			0 -> exit({badmatch,Dir});
+		    case string:find(Dir, D) of
+			nomatch -> exit({badmatch,Dir});
 			_ -> ok	    
 		    end,
 		    {[{start_time,DT}|Config],Evs};
@@ -1373,7 +1373,7 @@ delete_dirs(LogDir) ->
     Dirs2Del =
 	lists:foldl(fun(Dir, Del) ->
 			    [S,Mi,H,D,Mo,Y|_] = 
-				lists:reverse(string:tokens(Dir, [$.,$-,$_])),
+				lists:reverse(string:lexemes(Dir, [$.,$-,$_])),
 			    S2I = fun(Str) -> list_to_integer(Str) end,
 			    DT = {{S2I(Y),S2I(Mo),S2I(D)}, {S2I(H),S2I(Mi),S2I(S)}},
 			    Then = calendar:datetime_to_gregorian_seconds(DT),
diff --git a/lib/common_test/test/ct_unicode_SUITE.erl b/lib/common_test/test/ct_unicode_SUITE.erl
index 355503a5dc..6f6ec97ceb 100644
--- a/lib/common_test/test/ct_unicode_SUITE.erl
+++ b/lib/common_test/test/ct_unicode_SUITE.erl
@@ -191,7 +191,7 @@ check_logs(Dirs) ->
         [] ->
             ok;
         Match ->
-            MatchStr = string:join(Match,"\n"),
+            MatchStr = lists:join("\n",Match),
             ct:log("ERROR: Escaped unicode characters found in:~n~ts",[MatchStr]),
             ct:fail(escaped_unicode_characters_found)
     end.
diff --git a/lib/common_test/test/ct_userconfig_callback.erl b/lib/common_test/test/ct_userconfig_callback.erl
index c723f4ca1c..14e3d9a688 100644
--- a/lib/common_test/test/ct_userconfig_callback.erl
+++ b/lib/common_test/test/ct_userconfig_callback.erl
@@ -21,7 +21,7 @@
 -export([check_parameter/1, read_config/1]).
 
 read_config(Str) ->
-    KeyVals = string:tokens(Str, " "),
+    KeyVals = string:lexemes(Str, " "),
     {ok,read_config1(KeyVals)}.
 
 read_config1([Key,Val | KeyVals]) ->
diff --git a/lib/common_test/test/erl2html2_SUITE.erl b/lib/common_test/test/erl2html2_SUITE.erl
index 53a63578b2..b2336ff0bc 100644
--- a/lib/common_test/test/erl2html2_SUITE.erl
+++ b/lib/common_test/test/erl2html2_SUITE.erl
@@ -214,10 +214,10 @@ check_line_number(Last,Line,OrigLine) ->
 	    [$>|Rest] = lists:dropwhile(fun($>) -> false; (_) -> true end,Line),
 	    check_line_number(Last,Rest,OrigLine);
 	_ ->
-	    [N |_] = string:tokens(Line,":"),
+	    [N |_] = string:lexemes(Line,":"),
 %	    erlang:display(N),
 	    Num =
-		try list_to_integer(string:strip(N))
+		try list_to_integer(string:trim(N,both,"\s"))
 		catch _:_ -> ct:fail({no_line_number_after,Last,OrigLine})
 		end,
 	    if Num == Last+1 ->
diff --git a/lib/common_test/test/telnet_server.erl b/lib/common_test/test/telnet_server.erl
index 65300b0bdf..cef7784333 100644
--- a/lib/common_test/test/telnet_server.erl
+++ b/lib/common_test/test/telnet_server.erl
@@ -249,7 +249,7 @@ do_handle_data("echo " ++ Data,State) ->
     send(Data++"\r\n> ",State),
     {ok,State};
 do_handle_data("echo_sep " ++ Data,State) ->
-    Msgs = string:tokens(Data," "),
+    Msgs = string:lexemes(Data," "),
     lists:foreach(fun(Msg) ->
 			  send(Msg,State),
 			  timer:sleep(10)
@@ -260,28 +260,28 @@ do_handle_data("echo_no_prompt " ++ Data,State) ->
     send(Data,State),
     {ok,State};
 do_handle_data("echo_ml " ++ Data,State) ->
-    Lines = string:tokens(Data," "),
-    ReturnData = string:join(Lines,"\n"),
+    Lines = string:lexemes(Data," "),
+    ReturnData = lists:flatten(lists:join("\n",Lines)),
     send(ReturnData++"\r\n> ",State),
     {ok,State};
 do_handle_data("echo_ml_no_prompt " ++ Data,State) ->
-    Lines = string:tokens(Data," "),
-    ReturnData = string:join(Lines,"\n"),
+    Lines = string:lexemes(Data," "),
+    ReturnData = lists:flatten(lists:join("\n",Lines)),
     send(ReturnData,State),
     {ok,State};
 do_handle_data("echo_loop " ++ Data,State) ->
-    [TStr|Lines] = string:tokens(Data," "),
-    ReturnData = string:join(Lines,"\n"),
+    [TStr|Lines] = string:lexemes(Data," "),
+    ReturnData = lists:flatten(lists:join("\n",Lines)),
     send_loop(list_to_integer(TStr),ReturnData,State),
     {ok,State};
 do_handle_data("echo_delayed_prompt "++Data,State) ->
-    [MsStr|EchoData] = string:tokens(Data, " "),
-    send(string:join(EchoData,"\n"),State),
+    [MsStr|EchoData] = string:lexemes(Data, " "),
+    send(lists:flatten(lists:join("\n",EchoData)),State),
     timer:sleep(list_to_integer(MsStr)),
     send("\r\n> ",State),
     {ok,State};
 do_handle_data("disconnect_after " ++WaitStr,State) ->
-    Wait = list_to_integer(string:strip(WaitStr,right,$\n)),
+    Wait = list_to_integer(string:trim(WaitStr,trailing,"\n")),
     dbg("Server will close connection in ~w ms...", [Wait]),
     erlang:send_after(Wait,self(),disconnect),
     {ok,State};
diff --git a/lib/common_test/test/test_server_SUITE.erl b/lib/common_test/test/test_server_SUITE.erl
index 50d8bdd1ac..edfaea1d08 100644
--- a/lib/common_test/test/test_server_SUITE.erl
+++ b/lib/common_test/test/test_server_SUITE.erl
@@ -71,7 +71,7 @@ init_per_testcase(_TestCase, Config) ->
 %% @spec end_per_testcase(TestCase, Config0) ->
 %%               void() | {save_config,Config1} | {fail,Reason}
 end_per_testcase(test_server_unicode, _Config) ->
-    [_,Host] = string:tokens(atom_to_list(node()), "@"),
+    [_,Host] = string:lexemes(atom_to_list(node()), "@"),
     N1 = list_to_atom("test_server_tester_latin1" ++ "@" ++ Host),
     N2 = list_to_atom("test_server_tester_utf8" ++ "@" ++ Host),
     test_server:stop_node(N1),
@@ -347,7 +347,7 @@ generate_and_run_unicode_test(Config0,Encoding) ->
     RunDir = get_latest_run_dir(LogDir),
     true = filelib:is_dir(RunDir),
 
-    LowerModStr = string:to_lower(ModStr),
+    LowerModStr = string:lowercase(ModStr),
     SuiteHtml = translate_filename(LowerModStr++".src.html",Encoding),
     true = filelib:is_regular(filename:join(RunDir,SuiteHtml)),
 
@@ -362,7 +362,7 @@ generate_and_run_unicode_test(Config0,Encoding) ->
 %% remote file system on master - i.e. they will use same file name
 %% mode as the master.
 start_node(Config,Name,Args) ->
-    [_,Host] = string:tokens(atom_to_list(node()), "@"),
+    [_,Host] = string:lexemes(atom_to_list(node()), "@"),
     ct:log("Trying to start ~w@~s~n",[Name,Host]),
     case test_server:start_node(Name, peer, [{args,Args}]) of
 	{error,Reason} ->
diff --git a/lib/common_test/test/test_server_test_lib.erl b/lib/common_test/test/test_server_test_lib.erl
index c18b89b178..e3d987a2ea 100644
--- a/lib/common_test/test/test_server_test_lib.erl
+++ b/lib/common_test/test/test_server_test_lib.erl
@@ -43,7 +43,7 @@ pre_init_per_testcase(_TC,Config,State) ->
     {start_slave(Config, 50),State}.
 
 start_slave(Config,_Level) ->
-    [_,Host] = string:tokens(atom_to_list(node()), "@"),
+    [_,Host] = string:lexemes(atom_to_list(node()), "@"),
     
     ct:log("Trying to start ~s~n", 
 	   ["test_server_tester@"++Host]),
diff --git a/lib/common_test/test_server/ts.erl b/lib/common_test/test_server/ts.erl
index 5bfea9f4de..330652e73f 100644
--- a/lib/common_test/test_server/ts.erl
+++ b/lib/common_test/test_server/ts.erl
@@ -583,7 +583,7 @@ is_list_of_suites(List) ->
 		      S = if is_atom(Suite) -> atom_to_list(Suite);
 			     true -> Suite
 			  end,
-		      try lists:last(string:tokens(S,"_")) of
+		      try lists:last(string:lexemes(S,"_")) of
 			  "SUITE" -> true;
 			  "suite" -> true;
 			  _ -> false
diff --git a/lib/common_test/test_server/ts_autoconf_win32.erl b/lib/common_test/test_server/ts_autoconf_win32.erl
index 52e5ac8e69..6f6caaeb70 100644
--- a/lib/common_test/test_server/ts_autoconf_win32.erl
+++ b/lib/common_test/test_server/ts_autoconf_win32.erl
@@ -228,7 +228,7 @@ make(Vars) ->
     end.
 
 find_make(MakeCmd, Vars) ->
-    [Make|_] = string:tokens(MakeCmd, " \t"),
+    [Make|_] = string:lexemes(MakeCmd, " \t"),
     case os:find_executable(Make) of
 	false ->
 	    {no, Vars};
@@ -248,9 +248,9 @@ javac(Vars) ->
     end.
 
 is_debug_build() ->
-    case catch string:str(erlang:system_info(system_version), "debug") of
-	Int when is_integer(Int), Int > 0 ->
-	    true;
-	_ ->
-	    false
+    case catch string:find(erlang:system_info(system_version), "debug") of
+        nomatch ->
+            false;
+	_Else ->
+	    true
     end.
diff --git a/lib/common_test/test_server/ts_erl_config.erl b/lib/common_test/test_server/ts_erl_config.erl
index 032593bdda..c7fe4ccf83 100644
--- a/lib/common_test/test_server/ts_erl_config.erl
+++ b/lib/common_test/test_server/ts_erl_config.erl
@@ -311,7 +311,7 @@ lib_dir(Vars, Lib) ->
 			  end,
 	    CLibDir = filename:join(CLibDirList),
 	    Cmd = "ls -d " ++ CLibDir ++ "*",
-	    XLibDir = lists:last(string:tokens(os:cmd(Cmd),"\n")),
+	    XLibDir = lists:last(string:lexemes(os:cmd(Cmd),"\n")),
 	    case file:list_dir(XLibDir) of
 		{error, enoent} ->
 		    [];
@@ -361,15 +361,11 @@ emu_vars(Vars) ->
      {erl_name, atom_to_list(lib:progname())}|Vars].
 
 is_source_build() ->
-    string:str(erlang:system_info(system_version), "[source]") > 0.
+    string:find(erlang:system_info(system_version), "source") =/= nomatch.
 
 is_debug_build() ->
-    case catch string:str(erlang:system_info(system_version), "debug") of
-	Int when is_integer(Int), Int > 0 ->
-	    true;
-	_ ->
-	    false
-    end.
+    string:find(erlang:system_info(system_version), "debug") =/= nomatch.
+
 %%
 %% ssl_libdir
 %%
diff --git a/lib/common_test/test_server/ts_install.erl b/lib/common_test/test_server/ts_install.erl
index c5631fb9c3..048e5493d2 100644
--- a/lib/common_test/test_server/ts_install.erl
+++ b/lib/common_test/test_server/ts_install.erl
@@ -115,7 +115,7 @@ get_vars(_, _, _, _) ->
 config_flags() ->
     case os:getenv("CONFIG_FLAGS") of
 	false -> [];
-	CF -> string:tokens(CF, " \t\n")
+	CF -> string:lexemes(CF, " \t\n")
     end.
 
 unix_autoconf(XConf) ->
@@ -127,7 +127,7 @@ unix_autoconf(XConf) ->
     Threads = [" --enable-shlib-thread-safety" ||
 		  erlang:system_info(threads) /= false],
     Debug = [" --enable-debug-mode" ||
-		string:str(erlang:system_info(system_version),"debug") > 0],
+		string:find(erlang:system_info(system_version),"debug") =/= nomatch],
     MXX_Build = [Y || Y <- config_flags(),
 		      Y == "--enable-m64-build"
 			  orelse Y == "--enable-m32-build"],
@@ -159,10 +159,8 @@ assign_vars([]) ->
 assign_vars([{VAR,FlagsStr} | VARs]) ->
     [{VAR,assign_vars(FlagsStr)} | assign_vars(VARs)];
 assign_vars(FlagsStr) ->
-    Flags = [assign_all_vars(Str,[]) || Str <- string:tokens(FlagsStr, [$ ])],
-    string:strip(lists:flatten(lists:map(fun(Flag) ->
-						 Flag ++ " "
-					 end, Flags)), right).
+    Flags = [assign_all_vars(Str,[]) || Str <- string:lexemes(FlagsStr, [$\s])],
+    lists:flatten(lists:join(" ", Flags)).
 
 assign_all_vars([$$ | Rest], FlagSoFar) ->
     {VarName,Rest1} = get_var_name(Rest, []),
@@ -292,7 +290,7 @@ add_vars(Vars0, Opts0) ->
 get_testcase_callback() ->
     case os:getenv("TS_TESTCASE_CALLBACK") of
 	ModFunc when is_list(ModFunc), ModFunc /= "" ->
-	    case string:tokens(ModFunc, " ") of
+	    case string:lexemes(ModFunc, " ") of
 		[_Mod,_Func] -> ModFunc;
 		_ -> ""
 	    end;
@@ -430,8 +428,8 @@ bind_type() ->
 					
 
 debug() ->
-    case string:str(erlang:system_info(system_version), "debug") of
-	0 -> "";
+    case string:find(erlang:system_info(system_version), "debug") of
+	nomatch -> "";
 	_ -> "/Debug"
     end.
 
diff --git a/lib/common_test/test_server/ts_lib.erl b/lib/common_test/test_server/ts_lib.erl
index ea039a2c2b..da8d676b18 100644
--- a/lib/common_test/test_server/ts_lib.erl
+++ b/lib/common_test/test_server/ts_lib.erl
@@ -99,7 +99,7 @@ specialized_specs(Dir,PostFix) ->
     sort_tests([begin
 		    DirPart = filename:dirname(Name),
 		    AppTest = hd(lists:reverse(filename:split(DirPart))),
-		    list_to_atom(string:substr(AppTest, 1, length(AppTest)-5))
+		    list_to_atom(string:slice(AppTest, 0, string:length(AppTest)-5))
 		end || Name <- Specs]).
 
 specs(Dir) ->
@@ -111,9 +111,9 @@ specs(Dir) ->
 			      [Spec,TestDir|_] =
 				  lists:reverse(filename:split(FullName)),
 			      [_TestSuffix|TDParts] = 
-				  lists:reverse(string:tokens(TestDir,[$_,$.])),
+				  lists:reverse(string:lexemes(TestDir,[$_,$.])),
 			      [_SpecSuffix|SParts] = 
-				  lists:reverse(string:tokens(Spec,[$_,$.])),
+				  lists:reverse(string:lexemes(Spec,[$_,$.])),
 			      if TDParts == SParts ->
 				      [filename_to_atom(FullName)];	  
 				 true ->
@@ -273,7 +273,7 @@ do_test(Rest, Vars, Test) ->
 get_arg([$(|Rest], Vars, Stop, _) ->		
     get_arg(Rest, Vars, Stop, []); 
 get_arg([Stop|Rest], Vars, Stop, Acc) ->
-    Arg = string:strip(lists:reverse(Acc)),
+    Arg = string:trim(lists:reverse(Acc),both,[$\s]),
     Subst = subst(Arg, Vars),
     {Subst,Rest};
 get_arg([C|Rest], Vars, Stop, Acc) ->
diff --git a/lib/common_test/test_server/ts_run.erl b/lib/common_test/test_server/ts_run.erl
index 2736010551..3f594236bc 100644
--- a/lib/common_test/test_server/ts_run.erl
+++ b/lib/common_test/test_server/ts_run.erl
@@ -464,4 +464,4 @@ split_one(Path) ->
     filename:split(Path).
 
 split_path(Path) ->
-    string:tokens(Path,";").
+    string:lexemes(Path,";").
diff --git a/lib/compiler/src/core_pp.erl b/lib/compiler/src/core_pp.erl
index cff6c7098b..2516a9a1e1 100644
--- a/lib/compiler/src/core_pp.erl
+++ b/lib/compiler/src/core_pp.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1999-2016. All Rights Reserved.
+%% Copyright Ericsson AB 1999-2017. All Rights Reserved.
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -464,7 +464,7 @@ indent(#ctxt{indent=N}) ->
 	N =< 0 ->
 	    "";
 	true ->
-	    string:chars($\t, N div ?TAB_WIDTH, spaces(N rem ?TAB_WIDTH))
+           lists:duplicate(N div ?TAB_WIDTH, $\t) ++ spaces(N rem ?TAB_WIDTH)
     end.
 
 nl_indent(Ctxt) -> [$\n|indent(Ctxt)].
diff --git a/lib/compiler/src/core_scan.erl b/lib/compiler/src/core_scan.erl
index 9f0676538f..a50a2ffa8d 100644
--- a/lib/compiler/src/core_scan.erl
+++ b/lib/compiler/src/core_scan.erl
@@ -200,8 +200,8 @@ pre_string(eof, Q, _, Sp, SoFar, Pos) ->
     pre_string_error(Q, Sp, SoFar, Pos).
 
 pre_string_error(Q, Sp, SoFar, Pos) ->
-    S = reverse(string:substr(SoFar, 1, string:chr(SoFar, Q)-1)),
-    pre_error({string,Q,string:substr(S, 1, 16)}, Sp, Pos).
+    [S,_] = string:split(SoFar, [Q]),
+    pre_error({string,Q,string:slice(string:reverse(S), 0, 16)}, Sp, Pos).
 
 pre_char([C|Cs], SoFar) -> pre_char(C, Cs, SoFar);
 pre_char([], _) -> more;
diff --git a/lib/compiler/src/v3_kernel_pp.erl b/lib/compiler/src/v3_kernel_pp.erl
index 53097d0d7d..ac91039ae0 100644
--- a/lib/compiler/src/v3_kernel_pp.erl
+++ b/lib/compiler/src/v3_kernel_pp.erl
@@ -491,7 +491,7 @@ indent(Ctxt) -> indent(Ctxt#ctxt.indent, Ctxt).
 indent(N, _Ctxt) when N =< 0 -> "";
 indent(N, Ctxt) ->
     T = Ctxt#ctxt.tab_width,
-    string:chars($\t, N div T, string:chars($\s, N rem T)).
+    lists:duplicate(N div T, $\t) ++ lists:duplicate(N rem T, $\s).
 
 nl_indent(Ctxt) -> [$\n|indent(Ctxt)].
 
@@ -508,7 +508,7 @@ unindent([$\t|T], N, Ctxt, C) ->
     if N >= Tab ->
 	    unindent(T, N - Tab, Ctxt, C);
        true ->
-	    unindent([string:chars($\s, Tab - N)|T], 0, Ctxt, C)
+            unindent([lists:duplicate(Tab - N, $\s)|T], 0, Ctxt, C)
     end;
 unindent([L|T], N, Ctxt, C) when is_list(L) ->
     unindent(L, N, Ctxt, [T|C]);
diff --git a/lib/debugger/src/i.erl b/lib/debugger/src/i.erl
index 62ce8d0e20..853fa529a0 100644
--- a/lib/debugger/src/i.erl
+++ b/lib/debugger/src/i.erl
@@ -30,7 +30,7 @@
 -import(lists, [sort/1,foreach/2]).
 
 iv() ->
-    Vsn = string:substr(filename:basename(code:lib_dir(debugger)), 10),
+    Vsn = string:slice(filename:basename(code:lib_dir(debugger)), 9),
     list_to_atom(Vsn).
 
 %% -------------------------------------------
diff --git a/lib/dialyzer/src/dialyzer_cl.erl b/lib/dialyzer/src/dialyzer_cl.erl
index 0617be6435..1e06d6e974 100644
--- a/lib/dialyzer/src/dialyzer_cl.erl
+++ b/lib/dialyzer/src/dialyzer_cl.erl
@@ -672,7 +672,7 @@ failed_anal_msg(Reason, LogCache) ->
 %%
 format_log_cache(LogCache) ->
   Str = lists:append(lists:reverse(LogCache)),
-  string:join(string:tokens(Str, "\n"), "\n  ").
+  lists:join("\n  ", string:lexemes(Str, "\n")).
 
 -spec store_warnings(#cl_state{}, [raw_warning()]) -> #cl_state{}.
 
diff --git a/lib/dialyzer/src/dialyzer_gui_wx.erl b/lib/dialyzer/src/dialyzer_gui_wx.erl
index b4b1872c12..b8414b7d8b 100644
--- a/lib/dialyzer/src/dialyzer_gui_wx.erl
+++ b/lib/dialyzer/src/dialyzer_gui_wx.erl
@@ -475,7 +475,7 @@ gui_loop(#gui_state{backend_pid = BackendPid, doc_plt = DocPlt,
       gui_loop(State);
     {BackendPid, ext_types, ExtTypes} ->
       Map = fun({M,F,A}) -> io_lib:format("~tp:~tp/~p",[M,F,A]) end,
-      ExtTypeString = string:join(lists:map(Map, ExtTypes), "\n"),
+      ExtTypeString = lists:join("\n", lists:map(Map, ExtTypes)),
       Msg = io_lib:format("The following remote types are being used "
 			  "but information about them is not available.\n"
 			  "The analysis might get more precise by including "
@@ -638,7 +638,7 @@ output_sms(#gui_state{frame = Frame}, Title, Message, Type) ->
 
 free_editor(#gui_state{gui = Wx, frame = Frame}, Title, Contents0) ->
   Contents = lists:flatten(Contents0),
-  Tokens = string:tokens(Contents, "\n"),
+  Tokens = string:lexemes(Contents, "\n"),
   NofLines = length(Tokens),
   LongestLine = lists:max([length(X) || X <- Tokens]),
   Height0 = NofLines * 25 + 80,
diff --git a/lib/dialyzer/src/dialyzer_races.erl b/lib/dialyzer/src/dialyzer_races.erl
index 7fe64c3e11..7602faa21d 100644
--- a/lib/dialyzer/src/dialyzer_races.erl
+++ b/lib/dialyzer/src/dialyzer_races.erl
@@ -1270,8 +1270,8 @@ filter_named_tables(NamesList) ->
     [] -> [];
     [Head|Tail] ->
       NewHead =
-        case string:rstr(Head, "()") of
-          0 -> [Head];
+        case string:find(Head, "()", trailing) of
+          nomatch -> [Head];
           _Other -> []
         end,
       NewHead ++ filter_named_tables(Tail)
@@ -1558,8 +1558,8 @@ any_args(StrList) ->
   case StrList of
     [] -> false;
     [Head|Tail] ->
-      case string:rstr(Head, "()") of
-        0 -> any_args(Tail);
+      case string:find(Head, "()", trailing) of
+        nomatch -> any_args(Tail);
         _Other -> true
       end
   end.
@@ -1765,10 +1765,8 @@ ets_list_args(MaybeList) ->
   end.
 
 ets_list_argtypes(ListStr) ->
-  ListStr1 = string:strip(ListStr, left, $[),
-  ListStr2 = string:strip(ListStr1, right, $]),
-  ListStr3 = string:strip(ListStr2, right, $.),
-  string:strip(ListStr3, right, $,).
+  ListStr1 = string:trim(ListStr, leading, "$["),
+  string:trim(ListStr1, trailing, "$]$.$,").
 
 ets_tuple_args(MaybeTuple) ->
   case is_tuple(MaybeTuple) of
@@ -1810,7 +1808,7 @@ ets_tuple_argtypes2_helper(TupleStr, ElemStr, NestingLevel) ->
             {[H|ElemStr], NestingLevel, false}
         end,
       case Return of
-        true -> string:tokens(NewElemStr, " |");
+        true -> string:lexemes(NewElemStr, " |");
         false ->
           ets_tuple_argtypes2_helper(T, NewElemStr, NewNestingLevel)
       end
@@ -1889,44 +1887,44 @@ format_args_2(StrArgList, Call) ->
   case Call of
     whereis ->
       lists_key_replace(2, StrArgList,
-	string:tokens(lists:nth(2, StrArgList), " |"));
+	string:lexemes(lists:nth(2, StrArgList), " |"));
     register ->
       lists_key_replace(2, StrArgList,
-	string:tokens(lists:nth(2, StrArgList), " |"));
+	string:lexemes(lists:nth(2, StrArgList), " |"));
     unregister ->
       lists_key_replace(2, StrArgList,
-	string:tokens(lists:nth(2, StrArgList), " |"));
+	string:lexemes(lists:nth(2, StrArgList), " |"));
     ets_new ->
       StrArgList1 = lists_key_replace(2, StrArgList,
-	string:tokens(lists:nth(2, StrArgList), " |")),
+	string:lexemes(lists:nth(2, StrArgList), " |")),
       lists_key_replace(4, StrArgList1,
-        string:tokens(ets_list_argtypes(lists:nth(4, StrArgList1)), " |"));
+        string:lexemes(ets_list_argtypes(lists:nth(4, StrArgList1)), " |"));
     ets_lookup ->
       StrArgList1 = lists_key_replace(2, StrArgList,
-        string:tokens(lists:nth(2, StrArgList), " |")),
+        string:lexemes(lists:nth(2, StrArgList), " |")),
       lists_key_replace(4, StrArgList1,
-        string:tokens(lists:nth(4, StrArgList1), " |"));
+        string:lexemes(lists:nth(4, StrArgList1), " |"));
     ets_insert ->
       StrArgList1 = lists_key_replace(2, StrArgList,
-        string:tokens(lists:nth(2, StrArgList), " |")),
+        string:lexemes(lists:nth(2, StrArgList), " |")),
       lists_key_replace(4, StrArgList1,
         ets_tuple_argtypes2(
         ets_tuple_argtypes1(lists:nth(4, StrArgList1), [], [], 0),
         []));
     mnesia_dirty_read1 ->
       lists_key_replace(2, StrArgList,
-        [mnesia_tuple_argtypes(T) || T <- string:tokens(
+        [mnesia_tuple_argtypes(T) || T <- string:lexemes(
         lists:nth(2, StrArgList), " |")]);
     mnesia_dirty_read2 ->
       lists_key_replace(2, StrArgList,
-        string:tokens(lists:nth(2, StrArgList), " |"));
+        string:lexemes(lists:nth(2, StrArgList), " |"));
     mnesia_dirty_write1 ->
       lists_key_replace(2, StrArgList,
-        [mnesia_record_tab(R) || R <- string:tokens(
+        [mnesia_record_tab(R) || R <- string:lexemes(
         lists:nth(2, StrArgList), " |")]);
     mnesia_dirty_write2 ->
       lists_key_replace(2, StrArgList,
-        string:tokens(lists:nth(2, StrArgList), " |"));
+        string:lexemes(lists:nth(2, StrArgList), " |"));
     function_call -> StrArgList
   end.
 
@@ -1943,18 +1941,16 @@ format_type(Type, State) ->
   erl_types:t_to_string(Type, R).
 
 mnesia_record_tab(RecordStr) ->
-  case string:str(RecordStr, "#") =:= 1 of
-    true ->
-      "'" ++
-        string:sub_string(RecordStr, 2, string:str(RecordStr, "{") - 1) ++
-        "'";
-    false -> RecordStr
+  case erl_scan:string(RecordStr) of
+    {ok, [{'#', _}, {atom, _, Name}|_], _} ->
+      io_lib:write_string(atom_to_list(Name), $');
+    _ -> RecordStr
   end.
 
 mnesia_tuple_argtypes(TupleStr) ->
-  TupleStr1 = string:strip(TupleStr, left, ${),
-  [TupleStr2|_T] = string:tokens(TupleStr1, " ,"),
-  lists:flatten(string:tokens(TupleStr2, " |")).
+  TupleStr1 = string:trim(TupleStr, leading, "${"),
+  [TupleStr2|_T] = string:lexemes(TupleStr1, " ,"),
+  lists:flatten(string:lexemes(TupleStr2, " |")).
 
 -spec race_var_map(var_to_map1(), var_to_map2(), dict:dict(), op()) ->
         dict:dict().
@@ -2237,7 +2233,7 @@ var_type_analysis(FunDefArgs, FunCallTypes, WarnVarArgs, RaceWarnTag,
       case lists_key_member_lists(Vars, FunVarArgs) of
         0 -> [Vars, WVA2, WVA3, WVA4];
         N when is_integer(N) ->
-          NewWVA2 = string:tokens(lists:nth(N + 1, FunVarArgs), " |"),
+          NewWVA2 = string:lexemes(lists:nth(N + 1, FunVarArgs), " |"),
           [Vars, NewWVA2, WVA3, WVA4]
       end;
     ?WARN_WHEREIS_UNREGISTER ->
@@ -2246,7 +2242,7 @@ var_type_analysis(FunDefArgs, FunCallTypes, WarnVarArgs, RaceWarnTag,
       case lists_key_member_lists(Vars, FunVarArgs) of
         0 -> [Vars, WVA2];
         N when is_integer(N) ->
-          NewWVA2 = string:tokens(lists:nth(N + 1, FunVarArgs), " |"),
+          NewWVA2 = string:lexemes(lists:nth(N + 1, FunVarArgs), " |"),
           [Vars, NewWVA2]
       end;
     ?WARN_ETS_LOOKUP_INSERT ->
@@ -2256,7 +2252,7 @@ var_type_analysis(FunDefArgs, FunCallTypes, WarnVarArgs, RaceWarnTag,
         case lists_key_member_lists(Vars1, FunVarArgs) of
           0 -> [Vars1, WVA2];
           N1 when is_integer(N1) ->
-            NewWVA2 = string:tokens(lists:nth(N1 + 1, FunVarArgs), " |"),
+            NewWVA2 = string:lexemes(lists:nth(N1 + 1, FunVarArgs), " |"),
             [Vars1, NewWVA2]
         end,
       Vars2 =
@@ -2286,10 +2282,10 @@ var_type_analysis(FunDefArgs, FunCallTypes, WarnVarArgs, RaceWarnTag,
           NewWVA2 =
             case Arity of
               1 ->
-                [mnesia_record_tab(R) || R <- string:tokens(
+                [mnesia_record_tab(R) || R <- string:lexemes(
                   lists:nth(2, FunVarArgs), " |")];
               2 ->
-                string:tokens(lists:nth(N + 1, FunVarArgs), " |")
+                string:lexemes(lists:nth(N + 1, FunVarArgs), " |")
             end,
           [Vars, NewWVA2|T]
       end
diff --git a/lib/dialyzer/test/dialyzer_common.erl b/lib/dialyzer/test/dialyzer_common.erl
index 48083a2731..1a8403f486 100644
--- a/lib/dialyzer/test/dialyzer_common.erl
+++ b/lib/dialyzer/test/dialyzer_common.erl
@@ -221,13 +221,9 @@ get_suites(Dir) ->
     end.
 
 suffix(String, Suffix) ->
-    case string:rstr(String, Suffix) of
-	0 -> no;
-	Index ->
-	    case string:substr(String, Index) =:= Suffix of
-		true -> {yes, string:sub_string(String,1,Index-1)};
-		false -> no
-	    end
+    case string:split(String, Suffix, trailing) of
+	[Prefix,[]] -> {yes, Prefix};
+        _ -> no
     end.
 
 -spec create_suite(string()) -> 'ok'.
diff --git a/lib/edoc/src/edoc_layout.erl b/lib/edoc/src/edoc_layout.erl
index eafab0588e..baa147410b 100644
--- a/lib/edoc/src/edoc_layout.erl
+++ b/lib/edoc/src/edoc_layout.erl
@@ -608,7 +608,7 @@ etypef([Cs | L], St, O, R, Opts) ->
 app_fix(L, Opts) ->
     try
         {"//" ++ R1,L2} = app_fix1(L, 1),
-        [App, Mod] = string:tokens(R1, "/"),
+        [App, Mod] = string:lexemes(R1, "/"),
         "//" ++ atom(App, Opts) ++ "/" ++ atom(Mod, Opts) ++ L2
     catch _:_ -> L
     end.
@@ -1120,13 +1120,13 @@ ot_integer(E) ->
     {integer,0,list_to_integer(get_attrval(value, E))}.
 
 ot_range(E) ->
-    [I1, I2] = string:tokens(get_attrval(value, E), "."),
+    [I1, I2] = string:lexemes(get_attrval(value, E), "."),
     {type,0,range,[{integer,0,list_to_integer(I1)},
                    {integer,0,list_to_integer(I2)}]}.
 
 ot_binary(E) ->
     {Base, Unit} =
-        case string:tokens(get_attrval(value, E), ",:*><") of
+        case string:lexemes(get_attrval(value, E), ",:*><") of
             [] ->
                 {0, 0};
             ["_",B] ->
diff --git a/lib/edoc/src/edoc_specs.erl b/lib/edoc/src/edoc_specs.erl
index fb04bfce0e..26b7202462 100644
--- a/lib/edoc/src/edoc_specs.erl
+++ b/lib/edoc/src/edoc_specs.erl
@@ -83,7 +83,7 @@ spec(Form, Clause) ->
 %% the given Erlang spec and an empty list of arguments.
 dummy_spec(Form) ->
     {#t_name{name = Name}, Arity, TypeSpecs} = get_spec(Form),
-    As = string:join(lists:duplicate(Arity, "_X"), ","),
+    As = lists:join(",", lists:duplicate(Arity, "_X")),
     S = lists:flatten(io_lib:format("~p(~s) -> true\n", [Name, As])),
     #tag{name = spec, line = get_line(element(2, hd(TypeSpecs))),
          origin = code, data = S}.
diff --git a/lib/eldap/src/eldap.erl b/lib/eldap/src/eldap.erl
index 625309271b..2b84872b92 100644
--- a/lib/eldap/src/eldap.erl
+++ b/lib/eldap/src/eldap.erl
@@ -1368,9 +1368,9 @@ rm_leading_slash(Tail)      -> Tail.
 parse_attributes([$?|Tail]) ->
     case split_string(Tail,$?) of
         {[],Attributes} ->
-	    {[],{attributes,string:tokens(Attributes,",")}};
+	    {[],{attributes,string:lexemes(Attributes,",")}};
         {Attributes,Rest} ->
-            {Rest,{attributes,string:tokens(Attributes,",")}}
+            {Rest,{attributes,string:lexemes(Attributes,",")}}
     end.
 
 parse_hostport(Str) ->
diff --git a/lib/erl_docgen/src/docgen_edoc_xml_cb.erl b/lib/erl_docgen/src/docgen_edoc_xml_cb.erl
index 7cdbb502d9..67e6e33c93 100644
--- a/lib/erl_docgen/src/docgen_edoc_xml_cb.erl
+++ b/lib/erl_docgen/src/docgen_edoc_xml_cb.erl
@@ -11,7 +11,7 @@
 %% limitations under the License.
 %%
 %% Copyright (c) 2001-2016 Richard Carlsson. Parts written by Ericsson
-%% are Copyright (c) Ericsson AB 2001-2012. All Rights Reserved.
+%% are Copyright (c) Ericsson AB 2001-2017. All Rights Reserved.
 %%
 
 -module(docgen_edoc_xml_cb).
@@ -113,7 +113,7 @@ root_attributes(Element, Opts) ->
 %% epp:default_encoding/0 returns 'utf8'
 reformat_encoding(utf8) -> "UTF-8";
 reformat_encoding(List) when is_list(List) ->
-    case string:to_lower(List) of
+    case string:lowercase(List) of
         "utf8" -> "UTF-8";
         _ -> List
     end;
diff --git a/lib/erl_docgen/src/docgen_otp_specs.erl b/lib/erl_docgen/src/docgen_otp_specs.erl
index 126229ecc9..9f2b401f93 100644
--- a/lib/erl_docgen/src/docgen_otp_specs.erl
+++ b/lib/erl_docgen/src/docgen_otp_specs.erl
@@ -297,7 +297,7 @@ indent(L) ->
 app_fix(L) ->
     try
         {"//" ++ R1,L2} = app_fix(L, 1),
-        [App, Mod] = string:tokens(R1, "/"),
+        [App, Mod] = string:lexemes(R1, "/"),
         "//" ++ atom(App) ++ "/" ++ atom(Mod) ++ L2
     catch _:_ -> L
     end.
@@ -585,13 +585,13 @@ ot_integer(E) ->
     {integer,0,list_to_integer(get_attrval(value, E))}.
 
 ot_range(E) ->
-    [I1, I2] = string:tokens(get_attrval(value, E), "."),
+    [I1, I2] = string:lexemes(get_attrval(value, E), "."),
     {type,0,range,[{integer,0,list_to_integer(I1)},
                    {integer,0,list_to_integer(I2)}]}.
 
 ot_binary(E) ->
     {Base, Unit} =
-        case string:tokens(get_attrval(value, E), ",:*><") of
+        case string:lexemes(get_attrval(value, E), ",:*><") of
             [] ->
                 {0, 0};
             ["_",B] ->
diff --git a/lib/et/src/et_collector.erl b/lib/et/src/et_collector.erl
index b0f016a8ea..ffe244324c 100644
--- a/lib/et/src/et_collector.erl
+++ b/lib/et/src/et_collector.erl
@@ -1135,7 +1135,7 @@ handle_info(Info, S) ->
     noreply(S).
 
 listen_on_trace_port(Node, Port, S) ->
-    [_Name, Host] = string:tokens(atom_to_list(Node), [$@]),
+    [_Name, Host] = string:lexemes(atom_to_list(Node), [$@]),
     case catch start_trace_client(self(), ip, {Host, Port}) of
         {trace_client_pid, RemotePid} ->
             rpc:call(Node, et_selector, change_pattern, [S#state.trace_pattern]),
diff --git a/lib/eunit/src/eunit_lib.erl b/lib/eunit/src/eunit_lib.erl
index e340f50a3c..d1bd160ea1 100644
--- a/lib/eunit/src/eunit_lib.erl
+++ b/lib/eunit/src/eunit_lib.erl
@@ -391,7 +391,7 @@ fun_parent(F) ->
 
 -ifdef(TEST).
 fun_parent_test() ->
-    {?MODULE,fun_parent_test,0} = fun_parent(fun () -> ok end).
+    {?MODULE,fun_parent_test,0} = fun_parent(fun (A) -> {ok,A} end).
 -endif.
 
 %% ---------------------------------------------------------------------
diff --git a/lib/hipe/cerl/erl_types.erl b/lib/hipe/cerl/erl_types.erl
index f4746fc9d0..df9e7bdede 100644
--- a/lib/hipe/cerl/erl_types.erl
+++ b/lib/hipe/cerl/erl_types.erl
@@ -4249,13 +4249,13 @@ t_to_string(?identifier(Set), _RecDict) ->
   case Set of
     ?any -> "identifier()";
     _ ->
-      string:join([flat_format("~w()", [T]) || T <- set_to_list(Set)], " | ")
+      flat_join([flat_format("~w()", [T]) || T <- set_to_list(Set)], " | ")
   end;
 t_to_string(?opaque(Set), RecDict) ->
-  string:join([opaque_type(Mod, Name, Args, S, RecDict) ||
-                #opaque{mod = Mod, name = Name, struct = S, args = Args}
-                  <- set_to_list(Set)],
-	      " | ");
+  flat_join([opaque_type(Mod, Name, Args, S, RecDict) ||
+              #opaque{mod = Mod, name = Name, struct = S, args = Args}
+                <- set_to_list(Set)],
+            " | ");
 t_to_string(?matchstate(Pres, Slots), RecDict) ->
   flat_format("ms(~ts,~ts)", [t_to_string(Pres, RecDict),
                               t_to_string(Slots,RecDict)]);
@@ -4346,9 +4346,9 @@ t_to_string(?map(Pairs0,DefK,DefV), RecDict) ->
 		  end end,
   StrMand = [{Tos(K),Tos(V)}||{K,?mand,V}<-Pairs],
   StrOpt  = [{Tos(K),Tos(V)}||{K,?opt,V}<-Pairs],
-  "#{" ++ string:join([K ++ ":=" ++ V||{K,V}<-StrMand]
-		      ++ [K ++ "=>" ++ V||{K,V}<-StrOpt]
-		      ++ ExtraEl, ", ") ++ "}";
+  "#{" ++ flat_join([K ++ ":=" ++ V||{K,V}<-StrMand]
+                    ++ [K ++ "=>" ++ V||{K,V}<-StrOpt]
+                    ++ ExtraEl, ", ") ++ "}";
 t_to_string(?tuple(?any, ?any, ?any), _RecDict) -> "tuple()";
 t_to_string(?tuple(Elements, _Arity, ?any), RecDict) ->   
   "{" ++ comma_sequence(Elements, RecDict) ++ "}";
@@ -4371,7 +4371,7 @@ t_to_string(?var(Id), _RecDict) when is_integer(Id) ->
 
 record_to_string(Tag, [_|Fields], FieldNames, RecDict) ->
   FieldStrings = record_fields_to_string(Fields, FieldNames, RecDict, []),
-  "#" ++ atom_to_string(Tag) ++ "{" ++ string:join(FieldStrings, ",") ++ "}".
+  "#" ++ atom_to_string(Tag) ++ "{" ++ flat_join(FieldStrings, ",") ++ "}".
 
 record_fields_to_string([F|Fs], [{FName, _Abstr, DefType}|FDefs],
                         RecDict, Acc) ->
@@ -4397,7 +4397,7 @@ record_field_diffs_to_string(?tuple([_|Fs], Arity, Tag), RecDict) ->
   {ok, FieldNames} = lookup_record(TagAtom, Arity-1, RecDict),
   %% io:format("RecCElems = ~p\nRecTypes = ~p\n", [Fs, FieldNames]),
   FieldDiffs = field_diffs(Fs, FieldNames, RecDict, []),
-  string:join(FieldDiffs, " and ").
+  flat_join(FieldDiffs, " and ").
 
 field_diffs([F|Fs], [{FName, _Abstr, DefType}|FDefs], RecDict, Acc) ->
   %% Don't care about opacity for now.
@@ -4417,11 +4417,11 @@ comma_sequence(Types, RecDict) ->
 	    true -> "_";
 	    false -> t_to_string(T, RecDict)
 	  end || T <- Types],
-  string:join(List, ",").
+  flat_join(List, ",").
 
 union_sequence(Types, RecDict) ->
   List = [t_to_string(T, RecDict) || T <- Types], 
-  string:join(List, " | ").
+  flat_join(List, " | ").
 
 -ifdef(DEBUG).
 opaque_type(Mod, Name, _Args, S, RecDict) ->
@@ -5236,7 +5236,7 @@ t_form_to_string({ann_type, _L, [Var, Type]}) ->
 t_form_to_string({paren_type, _L, [Type]}) ->
   flat_format("(~ts)", [t_form_to_string(Type)]);
 t_form_to_string({remote_type, _L, [{atom, _, Mod}, {atom, _, Name}, Args]}) ->
-  ArgString = "(" ++ string:join(t_form_to_string_list(Args), ",") ++ ")",
+  ArgString = "(" ++ flat_join(t_form_to_string_list(Args), ",") ++ ")",
   flat_format("~w:~tw", [Mod, Name]) ++ ArgString;
 t_form_to_string({type, _L, arity, []}) -> "arity()";
 t_form_to_string({type, _L, binary, []}) -> "binary()";
@@ -5259,7 +5259,7 @@ t_form_to_string({type, _L, 'fun', []}) -> "fun()";
 t_form_to_string({type, _L, 'fun', [{type, _, any}, Range]}) ->
   "fun(...) -> " ++ t_form_to_string(Range);
 t_form_to_string({type, _L, 'fun', [{type, _, product, Domain}, Range]}) ->
-  "fun((" ++ string:join(t_form_to_string_list(Domain), ",") ++ ") -> "
+  "fun((" ++ flat_join(t_form_to_string_list(Domain), ",") ++ ") -> "
     ++ t_form_to_string(Range) ++ ")";
 t_form_to_string({type, _L, iodata, []}) -> "iodata()";
 t_form_to_string({type, _L, iolist, []}) -> "iolist()";
@@ -5267,7 +5267,7 @@ t_form_to_string({type, _L, list, [Type]}) ->
   "[" ++ t_form_to_string(Type) ++ "]";
 t_form_to_string({type, _L, map, any}) -> "map()";
 t_form_to_string({type, _L, map, Args}) ->
-  "#{" ++ string:join(t_form_to_string_list(Args), ",") ++ "}";
+  "#{" ++ flat_join(t_form_to_string_list(Args), ",") ++ "}";
 t_form_to_string({type, _L, map_field_assoc, [Key, Val]}) ->
   t_form_to_string(Key) ++ "=>" ++ t_form_to_string(Val);
 t_form_to_string({type, _L, map_field_exact, [Key, Val]}) ->
@@ -5279,7 +5279,7 @@ t_form_to_string({type, _L, nonempty_list, [Type]}) ->
   "[" ++ t_form_to_string(Type) ++ ",...]";
 t_form_to_string({type, _L, nonempty_string, []}) -> "nonempty_string()";
 t_form_to_string({type, _L, product, Elements}) ->
-  "<" ++ string:join(t_form_to_string_list(Elements), ",") ++ ">";
+  "<" ++ flat_join(t_form_to_string_list(Elements), ",") ++ ">";
 t_form_to_string({type, _L, range, [From, To]} = Type) ->
   case {erl_eval:partial_eval(From), erl_eval:partial_eval(To)} of
     {{integer, _, FromVal}, {integer, _, ToVal}} ->
@@ -5289,7 +5289,7 @@ t_form_to_string({type, _L, range, [From, To]} = Type) ->
 t_form_to_string({type, _L, record, [{atom, _, Name}]}) ->
   flat_format("#~tw{}", [Name]);
 t_form_to_string({type, _L, record, [{atom, _, Name}|Fields]}) ->
-  FieldString = string:join(t_form_to_string_list(Fields), ","),
+  FieldString = flat_join(t_form_to_string_list(Fields), ","),
   flat_format("#~tw{~ts}", [Name, FieldString]);
 t_form_to_string({type, _L, field_type, [{atom, _, Name}, Type]}) ->
   flat_format("~tw::~ts", [Name, t_form_to_string(Type)]);
@@ -5297,9 +5297,9 @@ t_form_to_string({type, _L, term, []}) -> "term()";
 t_form_to_string({type, _L, timeout, []}) -> "timeout()";
 t_form_to_string({type, _L, tuple, any}) -> "tuple()";
 t_form_to_string({type, _L, tuple, Args}) ->
-  "{" ++ string:join(t_form_to_string_list(Args), ",") ++ "}";
+  "{" ++ flat_join(t_form_to_string_list(Args), ",") ++ "}";
 t_form_to_string({type, _L, union, Args}) ->
-  string:join(t_form_to_string_list(Args), " | ");
+  flat_join(t_form_to_string_list(Args), " | ");
 t_form_to_string({type, _L, Name, []} = T) ->
    try
      M = mod,
@@ -5317,7 +5317,7 @@ t_form_to_string({type, _L, Name, []} = T) ->
   end;
 t_form_to_string({user_type, _L, Name, List}) ->
   flat_format("~tw(~ts)",
-              [Name, string:join(t_form_to_string_list(List), ",")]);
+              [Name, flat_join(t_form_to_string_list(List), ",")]);
 t_form_to_string({type, L, Name, List}) ->
   %% Compatibility: modules compiled before Erlang/OTP 18.0.
   t_form_to_string({user_type, L, Name, List}).
@@ -5584,7 +5584,7 @@ set_to_string(Set) ->
 	 true -> io_lib:write_string(atom_to_list(X), $'); % stupid emacs '
 	 false -> flat_format("~tw", [X])
        end || X <- set_to_list(Set)],
-  string:join(L, " | ").
+  flat_join(L, " | ").
 
 set_min([H|_]) -> H.
 
@@ -5594,6 +5594,9 @@ set_max(Set) ->
 flat_format(F, S) ->
   lists:flatten(io_lib:format(F, S)).
 
+flat_join(List, Sep) ->
+  lists:flatten(lists:join(Sep, List)).
+
 %%=============================================================================
 %% 
 %% Utilities for the binary type
diff --git a/lib/hipe/llvm/hipe_llvm.erl b/lib/hipe/llvm/hipe_llvm.erl
index 641d3fda0a..ccd40162cb 100644
--- a/lib/hipe/llvm/hipe_llvm.erl
+++ b/lib/hipe/llvm/hipe_llvm.erl
@@ -1005,11 +1005,12 @@ pp_ins(Dev, Ver, I) ->
       write(Dev, [" ", adj_stack_offset(I),")\n"]);
     #llvm_meta{} ->
       write(Dev, ["!", meta_id(I), " = !{ "]),
-      write(Dev, string:join([if is_list(Op) -> ["!\"", Op, "\""];
-				 is_integer(Op) -> ["i32 ", integer_to_list(Op)];
-				 is_record(Op, llvm_meta) ->
-				  ["!", meta_id(Op)]
-			      end || Op <- meta_operands(I)], ", ")),
+      write(Dev, lists:join(", ",
+                            [if is_list(Op) -> ["!\"", Op, "\""];
+                                is_integer(Op) -> ["i32 ", integer_to_list(Op)];
+                                is_record(Op, llvm_meta) ->
+                                 ["!", meta_id(Op)]
+                             end || Op <- meta_operands(I)])),
       write(Dev, " }\n");
     Other ->
       exit({?MODULE, pp_ins, {"Unknown LLVM instruction", Other}})
diff --git a/lib/hipe/llvm/hipe_llvm_main.erl b/lib/hipe/llvm/hipe_llvm_main.erl
index 4eec0c752b..54c435c127 100644
--- a/lib/hipe/llvm/hipe_llvm_main.erl
+++ b/lib/hipe/llvm/hipe_llvm_main.erl
@@ -154,7 +154,7 @@ compiler_target_opt() ->
 
 %% @doc Join options.
 fix_opts(Opts) ->
-  string:join(Opts, " ").
+  lists:flatten(lists:join(" ", Opts)).
 
 %% @doc Translate optimization-level flag (default is "O2").
 trans_optlev_flag(Tool, Options) ->
diff --git a/lib/hipe/llvm/hipe_rtl_to_llvm.erl b/lib/hipe/llvm/hipe_rtl_to_llvm.erl
index 79e1bfd381..934717efc1 100644
--- a/lib/hipe/llvm/hipe_rtl_to_llvm.erl
+++ b/lib/hipe/llvm/hipe_rtl_to_llvm.erl
@@ -1537,7 +1537,7 @@ declare_switch_table({Name, {switch, {TableType, Labels, _, _}, _}}, FunName) ->
   LabelList = [mk_jump_label(L) || L <- Labels],
   Fun1 = fun(X) -> "i8* blockaddress(@" ++ FunName ++ ", " ++ X ++ ")" end,
   List2 = lists:map(Fun1, LabelList),
-  List3 = string:join(List2, ",\n"),
+  List3 = lists:flatten(lists:join(",\n", List2)),
   List4 = "[\n" ++ List3 ++ "\n]\n",
   hipe_llvm:mk_const_decl("@" ++ Name, "constant", TableType, List4).
 
@@ -1553,7 +1553,7 @@ declare_closure_labels(ClosureLabels, Relocs, Fun) ->
   Relocs1 = relocs_store("table_closures", {table_closures, ArityList}, Relocs),
   List2 =
     ["i8* blockaddress(@" ++ FunName ++ ", " ++ L ++ ")" || L <- LabelList],
-  List3 = string:join(List2, ",\n"),
+  List3 = lists:flatten(lists:join(",\n", List2)),
   List4 = "[\n" ++ List3 ++ "\n]\n",
   NrLabels = length(LabelList),
   ByteTyPtr = hipe_llvm:mk_pointer(hipe_llvm:mk_int(?BITS_IN_BYTE)),
diff --git a/lib/hipe/main/hipe.erl b/lib/hipe/main/hipe.erl
index 19b4e8bfe2..f5f5bf5830 100644
--- a/lib/hipe/main/hipe.erl
+++ b/lib/hipe/main/hipe.erl
@@ -1616,11 +1616,11 @@ llvm_support_available() ->
 get_llvm_version() ->
   OptStr = os:cmd("opt -version"),
   SubStr = "LLVM version ", N = length(SubStr),
-  case string:str(OptStr, SubStr) of
-     0 -> % No opt available
+  case string:find(OptStr, SubStr) of
+     nomatch -> % No opt available
        {0, 0};
      S ->
-       case string:tokens(string:sub_string(OptStr, S + N), ".") of
+       case string:lexemes(string:slice(S, N), ".") of
 	 [MajorS, MinorS | _] ->
 	   case {string:to_integer(MajorS), string:to_integer(MinorS)} of
 	     {{Major, ""}, {Minor, _}}
diff --git a/lib/hipe/test/hipe_testsuite_driver.erl b/lib/hipe/test/hipe_testsuite_driver.erl
index 88576775ca..ee9c57a908 100644
--- a/lib/hipe/test/hipe_testsuite_driver.erl
+++ b/lib/hipe/test/hipe_testsuite_driver.erl
@@ -29,13 +29,9 @@ get_suites(SuitesWithSuiteSuffix) ->
     [S || {yes, S} <- Prefixes].
 
 suffix(String, Suffix) ->
-    case string:rstr(String, Suffix) of
-	0 -> no;
-	Index ->
-	    case string:substr(String, Index) =:= Suffix of
-		true -> {yes, string:sub_string(String, 1, Index-1)};
-		false -> no
-	    end
+    case string:split(String, Suffix, trailing) of
+	[Prefix,[]] -> {yes, Prefix};
+        _ -> no
     end.
 
 -spec file_type(file:filename()) -> {ok, file_type()} | {error, ext_posix()}.
diff --git a/lib/hipe/test/opt_verify_SUITE.erl b/lib/hipe/test/opt_verify_SUITE.erl
index 86083fa02b..79bc2f1f73 100644
--- a/lib/hipe/test/opt_verify_SUITE.erl
+++ b/lib/hipe/test/opt_verify_SUITE.erl
@@ -59,7 +59,7 @@ call_elim_test_file(Config, FileName, Option) ->
 substring_count(Icode, Substring) ->
     substring_count(Icode, Substring, 0).
 substring_count(Icode, Substring, N) ->
-    case string:str(Icode, Substring) of
-        0 -> N;
-        I -> substring_count(lists:nthtail(I, Icode), Substring, N+1)
+    case string:find(Icode, Substring) of
+        nomatch -> N;
+        Prefix -> substring_count(string:prefix(Prefix, Substring), Substring, N+1)
     end.
diff --git a/lib/kernel/src/erl_boot_server.erl b/lib/kernel/src/erl_boot_server.erl
index ac81cc9689..2a38266579 100644
--- a/lib/kernel/src/erl_boot_server.erl
+++ b/lib/kernel/src/erl_boot_server.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2016. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -253,9 +253,9 @@ handle_info({udp, U, IP, Port, Data}, S0) ->
 				   "~w is not a valid address ** ~n", [IP]),
 	    {noreply,S0};
 	{true,_,_} ->
-	    case catch string:substr(Data, 1, length(?EBOOT_REQUEST)) of
+	    case catch string:slice(Data, 0, length(?EBOOT_REQUEST)) of
 		?EBOOT_REQUEST ->
-		    Vsn = string:substr(Data, length(?EBOOT_REQUEST)+1, length(Data)),
+		    Vsn = string:slice(Data, length(?EBOOT_REQUEST), length(Data)),
 		    error_logger:error_msg("** Illegal boot server connection attempt: "
 					   "client version is ~s ** ~n", [Vsn]);
 		_ ->
diff --git a/lib/kernel/src/erl_reply.erl b/lib/kernel/src/erl_reply.erl
index e1e046cbb4..e1c4ffe839 100644
--- a/lib/kernel/src/erl_reply.erl
+++ b/lib/kernel/src/erl_reply.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1997-2016. All Rights Reserved.
+%% Copyright Ericsson AB 1997-2017. All Rights Reserved.
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -42,7 +42,7 @@ reply(_) ->
 
 %% convert ip number to tuple
 ip_string_to_tuple(Ip) ->
-    [Ip1,Ip2,Ip3,Ip4] = string:tokens(Ip,"."),
+    [Ip1,Ip2,Ip3,Ip4] = string:lexemes(Ip,"."),
     {list_to_integer(Ip1),
      list_to_integer(Ip2),
      list_to_integer(Ip3),
diff --git a/lib/kernel/src/group.erl b/lib/kernel/src/group.erl
index bf785959ff..a5210901f2 100644
--- a/lib/kernel/src/group.erl
+++ b/lib/kernel/src/group.erl
@@ -793,9 +793,9 @@ search_up_stack(Stack, Substr) ->
     case up_stack(Stack) of
 	{none,NewStack} -> {none,NewStack};
 	{L, NewStack} ->
-	    case string:str(L, Substr) of
-		0 -> search_up_stack(NewStack, Substr);
-		_ -> {string:strip(L,right,$\n), NewStack}
+            case string:find(L, Substr) of
+                nomatch -> search_up_stack(NewStack, Substr);
+                _ -> {string:trim(L, trailing, "$\n"), NewStack}
 	    end
     end.
 
@@ -803,9 +803,9 @@ search_down_stack(Stack, Substr) ->
     case down_stack(Stack) of
 	{none,NewStack} -> {none,NewStack};
 	{L, NewStack} ->
-	    case string:str(L, Substr) of
-		0 -> search_down_stack(NewStack, Substr);
-		_ -> {string:strip(L,right,$\n), NewStack}
+	    case string:find(L, Substr) of
+		nomatch -> search_down_stack(NewStack, Substr);
+		_ -> {string:trim(L, trailing, "$\n"), NewStack}
 	    end
     end.
 
diff --git a/lib/kernel/src/inet_config.erl b/lib/kernel/src/inet_config.erl
index 4bbc520449..9f76360b8b 100644
--- a/lib/kernel/src/inet_config.erl
+++ b/lib/kernel/src/inet_config.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1997-2016. All Rights Reserved.
+%% Copyright Ericsson AB 1997-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -369,7 +369,7 @@ win32_load1(Reg,Type,HFileKey) ->
     end.
 
 win32_split_line(Line,nt) -> inet_parse:split_line(Line);
-win32_split_line(Line,windows) -> string:tokens(Line, ",").
+win32_split_line(Line,windows) -> string:lexemes(Line, ",").
 
 win32_get_strings(Reg, Names) ->
     win32_get_strings(Reg, Names, []).
diff --git a/lib/kernel/src/inet_dns.erl b/lib/kernel/src/inet_dns.erl
index d5f982cc51..f1f58bc872 100644
--- a/lib/kernel/src/inet_dns.erl
+++ b/lib/kernel/src/inet_dns.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1997-2016. All Rights Reserved.
+%% Copyright Ericsson AB 1997-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -29,7 +29,7 @@
 
 -export([decode/1, encode/1]).
 
--import(lists, [reverse/1, reverse/2, nthtail/2]).
+-import(lists, [reverse/1]).
 
 -include("inet_int.hrl").
 -include("inet_dns.hrl").
@@ -473,7 +473,7 @@ decode_data(<<Order:16,Preference:16,Data0/binary>>, _, ?S_NAPTR, Buffer) ->
     {Data2,Services} = decode_string(Data1),
     {Data,Regexp} = decode_characters(Data2, utf8),
     Replacement = decode_domain(Data, Buffer),
-    {Order,Preference,string:to_lower(Flags),string:to_lower(Services),
+    {Order,Preference,string:lowercase(Flags),string:lowercase(Services),
      Regexp,Replacement};
 %% ?S_OPT falls through to default
 decode_data(Data, _, ?S_TXT, _) ->
diff --git a/lib/kernel/src/inet_parse.erl b/lib/kernel/src/inet_parse.erl
index 29804dc50b..e9685c6554 100644
--- a/lib/kernel/src/inet_parse.erl
+++ b/lib/kernel/src/inet_parse.erl
@@ -95,7 +95,7 @@ hosts(Fname,File) ->
 		 %% interface with a %if suffix. These kind of
 		 %% addresses maybe need to be gracefully handled
 		 %% throughout inet* and inet_drv.
-		 case string:tokens(Address, "%") of
+		 case string:lexemes(Address, "%") of
 		     [Addr,_] ->
 			 {ok,_} = address(Addr),
 			 skip;
@@ -407,7 +407,7 @@ is_dom1([C | Cs]) when C >= $a, C =< $z -> is_dom_ldh(Cs);
 is_dom1([C | Cs]) when C >= $A, C =< $Z -> is_dom_ldh(Cs);
 is_dom1([C | Cs]) when C >= $0, C =< $9 -> 
     case is_dom_ldh(Cs) of
-	true  -> is_dom2(string:tokens([C | Cs],"."));
+	true  -> is_dom2(string:lexemes([C | Cs],"."));
 	false -> false
     end;
 is_dom1(_) -> false.
diff --git a/lib/kernel/src/os.erl b/lib/kernel/src/os.erl
index 0250783632..209899d587 100644
--- a/lib/kernel/src/os.erl
+++ b/lib/kernel/src/os.erl
@@ -178,7 +178,7 @@ verify_executable(Name0, [Ext|Rest], OrigExtensions) ->
     end;
 verify_executable(Name, [], OrigExtensions) when OrigExtensions =/= [""] -> %% Windows
     %% Will only happen on windows, hence case insensitivity
-    case can_be_full_name(string:to_lower(Name),OrigExtensions) of
+    case can_be_full_name(string:lowercase(Name),OrigExtensions) of
 	true ->
 	    verify_executable(Name,[""],[""]);
 	_ ->
diff --git a/lib/mnesia/test/mnesia_test_lib.erl b/lib/mnesia/test/mnesia_test_lib.erl
index 0fabdc7929..78dbe7ffde 100644
--- a/lib/mnesia/test/mnesia_test_lib.erl
+++ b/lib/mnesia/test/mnesia_test_lib.erl
@@ -774,7 +774,7 @@ init_nodes([], _File, _Line) ->
 
 %% Returns [Name, Host]
 node_to_name_and_host(Node) ->
-    string:tokens(atom_to_list(Node), [$@]).
+    string:lexemes(atom_to_list(Node), [$@]).
 
 lookup_config(Key,Config) ->
     case lists:keysearch(Key,1,Config) of
diff --git a/lib/observer/src/cdv_dist_cb.erl b/lib/observer/src/cdv_dist_cb.erl
index 2b4c9f56d1..aeb34e5baf 100644
--- a/lib/observer/src/cdv_dist_cb.erl
+++ b/lib/observer/src/cdv_dist_cb.erl
@@ -78,7 +78,7 @@ init_gen_page(Parent, Info) ->
     cdv_info_wx:start_link(Parent,{Fields,Info,[]}).
 
 format({creations,Creations}) ->
-    string:join([integer_to_list(C) || C <- Creations],",");
+    lists:flatten(lists:join(",",[integer_to_list(C) || C <- Creations]));
 format(D) ->
     D.
 
diff --git a/lib/observer/src/cdv_mem_cb.erl b/lib/observer/src/cdv_mem_cb.erl
index abeddc7335..925487786c 100644
--- a/lib/observer/src/cdv_mem_cb.erl
+++ b/lib/observer/src/cdv_mem_cb.erl
@@ -49,9 +49,7 @@ gen_mem_info_fields([]) ->
     [].
 
 upper(Key) ->
-    string:join([string:to_upper([H]) ++ T || 
-		    [H|T] <- string:tokens(Key,"_")]," ").
-
+    lists:join(" ", [string:titlecase(Word) || Word <- string:split(Key, "_", all)]).
 
 %%%-----------------------------------------------------------------
 %%% Allocated areas page
diff --git a/lib/observer/src/cdv_wx.erl b/lib/observer/src/cdv_wx.erl
index 898f39ded2..8cc135d174 100644
--- a/lib/observer/src/cdv_wx.erl
+++ b/lib/observer/src/cdv_wx.erl
@@ -130,8 +130,9 @@ init(File0) ->
 	{ok,File} ->
 	    %% Set window title
 	    T1 = "Crashdump Viewer: ",
+            FileLength = string:length(File),
 	    Title =
-		if length(File) > 70 ->
+		if FileLength > 70 ->
 			T1 ++ filename:basename(File);
 		   true ->
 			T1 ++ File
@@ -419,8 +420,9 @@ load_dump(Frame,FileName) ->
 	ok    ->
 	    %% Set window title
 	    T1 = "Crashdump Viewer: ",
+            FileLength = string:length(FileName),
 	    Title =
-		if length(FileName) > 70 ->
+		if FileLength > 70 ->
 			T1 ++ filename:basename(FileName);
 		   true ->
 			T1 ++ FileName
diff --git a/lib/observer/src/crashdump_viewer.erl b/lib/observer/src/crashdump_viewer.erl
index fd8b3b9e67..31258cdf20 100644
--- a/lib/observer/src/crashdump_viewer.erl
+++ b/lib/observer/src/crashdump_viewer.erl
@@ -825,7 +825,7 @@ do_read_file(File) ->
 			    check_if_truncated(),
 			    [{DumpVsn0,_}] = lookup_index(?erl_crash_dump),
 			    DumpVsn = [list_to_integer(L) ||
-					L<-string:tokens(DumpVsn0,".")],
+					L<-string:lexemes(DumpVsn0,".")],
 			    Binaries = read_binaries(Fd,DumpVsn),
 			    close(Fd),
 			    {ok,Binaries,DumpVsn};
@@ -1235,12 +1235,12 @@ parse_monitor("{"++Str) ->
     %% Named process
     {Name,Node,Rest1} = parse_name_node(Str,[]),
     Pid = get_pid_from_name(Name,Node),
-    case parse_link(string:strip(Rest1,left,$,),[]) of
+    case parse_link(string:trim(Rest1,leading,","),[]) of
 	{Ref,"}"++Rest2} ->
 	    %% Bug in break.c - prints an extra "}" for remote
 	    %% nodes... thus the strip
 	    {{Pid,"{"++Name++","++Node++"} ("++Ref++")"},
-	     string:strip(Rest2,left,$})};
+	     string:trim(Rest2,leading,"}")};
 	{Ref,[]} ->
 	    {{Pid,"{"++Name++","++Node++"} ("++Ref++")"},[]}
     end;
@@ -1506,7 +1506,7 @@ get_ports(File) ->
 %% Converting port string to tuple to secure correct sorting. This is
 %% converted back in cdv_port_cb:format/1.
 port_to_tuple("#Port<"++Port) ->
-    [I1,I2] = string:tokens(Port,".>"),
+    [I1,I2] = string:lexemes(Port,".>"),
     {list_to_integer(I1),list_to_integer(I2)}.
 
 get_portinfo(Fd,Port) ->
@@ -1529,9 +1529,9 @@ get_portinfo(Fd,Port) ->
 	"Registered as" ->
 	    get_portinfo(Fd,Port#port{name=string(Fd)});
 	"Monitors" ->
-	    Monitors0 = string:tokens(bytes(Fd),"()"),
+	    Monitors0 = string:lexemes(bytes(Fd),"()"),
 	    Monitors = [begin
-			    [Pid,Ref] = string:tokens(Mon,","),
+			    [Pid,Ref] = string:lexemes(Mon,","),
 			    {Pid,Pid++" ("++Ref++")"}
 			end || Mon <- Monitors0],
 	    get_portinfo(Fd,Port#port{monitors=Monitors});
@@ -1592,7 +1592,7 @@ get_etsinfo(Fd,EtsTable = #ets_table{details=Ds},WS) ->
 	"Buckets" ->
 	    %% A bug in erl_db_hash.c prints a space after the buckets
 	    %% - need to strip the string to make list_to_integer/1 happy.
-	    Buckets = list_to_integer(string:strip(bytes(Fd))),
+	    Buckets = list_to_integer(string:trim(bytes(Fd),both,"\s")),
 	    get_etsinfo(Fd,EtsTable#ets_table{buckets=Buckets},WS);
 	"Objects" ->
 	    get_etsinfo(Fd,EtsTable#ets_table{size=list_to_integer(bytes(Fd))},WS);
@@ -1610,7 +1610,9 @@ get_etsinfo(Fd,EtsTable = #ets_table{details=Ds},WS) ->
 	    Val = bytes(Fd),
 	    get_etsinfo(Fd,EtsTable#ets_table{details=Ds#{chain_min=>Val}},WS);
 	"Chain Length Avg" ->
-	    Val = try list_to_float(string:strip(bytes(Fd))) catch _:_ -> "-" end,
+	    Val = try list_to_float(string:trim(bytes(Fd),both,"\s"))
+                  catch _:_ -> "-"
+                  end,
 	    get_etsinfo(Fd,EtsTable#ets_table{details=Ds#{chain_avg=>Val}},WS);
 	"Chain Length Max" ->
 	    Val = bytes(Fd),
@@ -1767,7 +1769,7 @@ get_nodeinfo(Fd,Nod) ->
 	    Creations = lists:flatmap(fun(C) -> try [list_to_integer(C)]
 						catch error:badarg -> []
 						end
-				      end, string:tokens(bytes(Fd)," ")),
+				      end, string:lexemes(bytes(Fd)," ")),
 	    get_nodeinfo(Fd,Nod#nod{creation={creations,Creations}});
 	"Remote link" ->
 	    Procs = bytes(Fd), % e.g. "<0.31.0> <4322.54.0>"
@@ -2213,7 +2215,7 @@ get_size_value(Key,Data) ->
 %% and Value is the sum over all allocator instances of each type.
 sort_allocator_types([{Name,Data}|Allocators],Acc,DoTotal) ->
     Type =
-	case string:tokens(Name,"[]") of
+	case string:lexemes(Name,"[]") of
 	    [T,_Id] -> T;
 	    [Name] -> Name;
             Other -> Other
diff --git a/lib/observer/src/observer_html_lib.erl b/lib/observer/src/observer_html_lib.erl
index 3dfcc42ada..92fc7cec92 100644
--- a/lib/observer/src/observer_html_lib.erl
+++ b/lib/observer/src/observer_html_lib.erl
@@ -278,24 +278,24 @@ href_proc_port("['#CDVPort'"++T,Acc,LTB) ->
     %% Port written by crashdump_viewer:parse_term(...)
     {Port0,Rest} = split($],T),
     PortStr=
-	case string:tokens(Port0,",.|") of
+	case string:lexemes(Port0,",.|") of
 	    [X,Y] ->
 		Port = "#Port&lt;"++X++"."++Y++"&gt;",
 		href(Port,Port);
 	Ns ->
-		"#Port&lt;" ++ string:join(Ns,".") ++"...&gt;"
+		"#Port&lt;" ++ lists:join($.,Ns) ++"...&gt;"
     end,
     href_proc_port(Rest,[PortStr|Acc],LTB);
 href_proc_port("['#CDVPid'"++T,Acc,LTB) ->
     %% Pid written by crashdump_viewer:parse_term(...)
     {Pid0,Rest} = split($],T),
     PidStr =
-	case string:tokens(Pid0,",.|") of
+	case string:lexemes(Pid0,",.|") of
 	    [X,Y,Z] ->
 		Pid = "&lt;"++X++"."++Y++"."++Z++"&gt;",
 		href(Pid,Pid);
 	    Ns ->
-		"&lt;" ++ string:join(Ns,".") ++ "...&gt;"
+		"&lt;" ++ lists:join($.,Ns) ++ "...&gt;"
 	end,
     href_proc_port(Rest,[PidStr|Acc],LTB);
 href_proc_port("'#CDVIncompleteHeap'"++T,Acc,LTB)->
@@ -332,7 +332,7 @@ href_proc_port([],Acc,_) ->
 href_proc_bin(From, T, Acc, LTB) ->
     {OffsetSizePos,Rest} = split($],T),
     BinStr =
-	case string:tokens(OffsetSizePos,",.| \n") of
+	case string:lexemes(OffsetSizePos,",.| \n") of
 	    [Offset,SizeStr,Pos] when From =:= cdv ->
                 Size = list_to_integer(SizeStr),
                 PreviewSize = min(Size,10),
diff --git a/lib/observer/src/observer_lib.erl b/lib/observer/src/observer_lib.erl
index 463fb5b8ef..658adf1c4a 100644
--- a/lib/observer/src/observer_lib.erl
+++ b/lib/observer/src/observer_lib.erl
@@ -477,7 +477,7 @@ create_box(Parent, Data) ->
 				 link_entry(Panel,Value);
 			     _ ->
 				 Value = to_str(Value0),
-                                 case string:sub_word(lists:sublist(Value, 80),1,$\n) of
+                                 case string:nth_lexeme(lists:sublist(Value, 80),1, [$\n]) of
                                      Value ->
                                          %% Short string, no newlines - show all
 					 wxStaticText:new(Panel, ?wxID_ANY, Value);
diff --git a/lib/observer/src/observer_procinfo.erl b/lib/observer/src/observer_procinfo.erl
index 963def958b..d1665cec06 100644
--- a/lib/observer/src/observer_procinfo.erl
+++ b/lib/observer/src/observer_procinfo.erl
@@ -454,7 +454,8 @@ local_pid_str(Pid) ->
 
 global_pid_node_pref(Pid) ->
     %% Global PID node prefix : X of <X.Y.Z>
-    string:strip(string:sub_word(pid_to_list(Pid),1,$.),left,$<).
+    [NodePrefix|_] = string:lexemes(pid_to_list(Pid),"<."),
+    NodePrefix.
 
 io_get_data(Pid) ->
     Pid ! {self(), get_data_and_close},
diff --git a/lib/observer/src/observer_wx.erl b/lib/observer/src/observer_wx.erl
index be93b1d5f1..453e3bdc2d 100644
--- a/lib/observer/src/observer_wx.erl
+++ b/lib/observer/src/observer_wx.erl
@@ -732,7 +732,7 @@ get_nodes() ->
     {Nodes, lists:reverse(Menues)}.
 
 epmd_nodes(Names) ->
-    [_, Host] = string:tokens(atom_to_list(node()),"@"),
+    [_, Host] = string:lexemes(atom_to_list(node()),"@"),
     [list_to_atom(Name ++ [$@|Host]) || {Name, _} <- Names].
 
 update_node_list(State = #state{menubar=MenuBar}) ->
diff --git a/lib/observer/src/ttb.erl b/lib/observer/src/ttb.erl
index 940fdc9818..29a572d7fe 100644
--- a/lib/observer/src/ttb.erl
+++ b/lib/observer/src/ttb.erl
@@ -100,7 +100,7 @@ do_tracer(Clients,PI,Traci) ->
 				 {ok, H} = inet:gethostname(),
 				 H;
 			     _ ->
-				 [_,H] = string:tokens(atom_to_list(N),"@"),
+				 [_,H] = string:lexemes(atom_to_list(N),"@"),
 				 H
 			 end,
 		  case catch dbg:tracer(N,port,dbg:trace_port(ip,IpPortSpec)) of
@@ -976,7 +976,7 @@ decode_filename(3,Bin,latin1) ->
     File.
 
 host(Node) ->
-    [_name,Host] = string:tokens(atom_to_list(Node),"@"),
+    [_name,Host] = string:lexemes(atom_to_list(Node),"@"),
     Host.
 
 wait_for_fetch([]) ->
@@ -1064,7 +1064,7 @@ collect_files(Dirs) ->
     lists:map(fun(Dir) ->
                       MetaFiles = filelib:wildcard(filename:join(Dir,"*.ti")),
                       lists:map(fun(M) ->
-                                        Sub = string:left(M,length(M)-3),
+                                        Sub = filename:rootname(M,".ti"),
                                         case filelib:is_file(Sub) of
                                             true -> Sub;
                                             false -> Sub++".*.wrp"
diff --git a/lib/observer/test/ttb_SUITE.erl b/lib/observer/test/ttb_SUITE.erl
index c06ec21f36..6d7e574856 100644
--- a/lib/observer/test/ttb_SUITE.erl
+++ b/lib/observer/test/ttb_SUITE.erl
@@ -222,7 +222,7 @@ file_fetch(Config) when is_list(Config) ->
     ?line ?t:capture_stop(),
     ?line [StoreString] = ?t:capture_get(),
     ?line UploadDir =
-	lists:last(string:tokens(lists:flatten(StoreString),"$ \n")),
+	lists:last(string:lexemes(lists:flatten(StoreString),"$ \n")),
 
     %% check that files are no longer in original directories...
     ?line ok = check_gone(ThisDir,atom_to_list(Node)++"-file_fetch"),
@@ -1035,8 +1035,8 @@ logfile_name_in_fetch_dir(Config) when is_list(Config) ->
     ?line {ServerNode, ClientNode} = start_client_and_server(),
     ?line begin_trace(ServerNode, ClientNode, {local, ?FNAME}),
     ?line {_,Dir} = ttb:stop([return_fetch_dir]),
-    ?line P1 = lists:nth(3, string:tokens(filename:basename(Dir), "_")),
-    ?line P2 = hd(string:tokens(P1, "-")),
+    ?line P1 = lists:nth(3, string:lexemes(filename:basename(Dir), "_")),
+    ?line P2 = hd(string:lexemes(P1, "-")),
     ?line _File = P2.
 logfile_name_in_fetch_dir(cleanup,_Config) ->
     ?line stop_client_and_server().
diff --git a/lib/os_mon/src/cpu_sup.erl b/lib/os_mon/src/cpu_sup.erl
index e758b63d19..c1c972b5b1 100644
--- a/lib/os_mon/src/cpu_sup.erl
+++ b/lib/os_mon/src/cpu_sup.erl
@@ -244,7 +244,7 @@ get_uint32_measurement(Request, #internal{os_type = {unix, Sys}}) when Sys == ir
     %% Get the load average using uptime.
     %% "8:01pm  up 2 days, 22:12,  4 users,  load average: 0.70, 0.58, 0.43"
     D = os:cmd("uptime") -- "\n",
-    Avg = lists:reverse(hd(string:tokens(lists:reverse(D), ":"))),
+    Avg = lists:reverse(hd(string:lexemes(lists:reverse(D), ":"))),
     {ok, [L1, L5, L15], _} = io_lib:fread("~f, ~f, ~f", Avg),
     case Request of
 	?avg1  -> sunify(L1);
diff --git a/lib/os_mon/src/memsup.erl b/lib/os_mon/src/memsup.erl
index 0a9a883390..95cb798ba5 100644
--- a/lib/os_mon/src/memsup.erl
+++ b/lib/os_mon/src/memsup.erl
@@ -705,7 +705,7 @@ get_os_wordsize_with_uname() ->
 	_         -> 32
     end.
 
-clean_string(String) -> lists:flatten(string:tokens(String,"\r\n\t ")).
+clean_string(String) -> lists:flatten(string:lexemes(String,"\r\n\t ")).
     
 
 %%--Replying to pending clients-----------------------------------------
diff --git a/lib/parsetools/src/leex.erl b/lib/parsetools/src/leex.erl
index e2e7d7359f..8a4a5e8d86 100644
--- a/lib/parsetools/src/leex.erl
+++ b/lib/parsetools/src/leex.erl
@@ -37,7 +37,6 @@
 -import(lists, [member/2,reverse/1,sort/1,delete/2,
                 keysort/2,keydelete/3,
                 map/2,foldl/3,foreach/2,flatmap/2]).
--import(string, [substr/2,substr/3,span/2]).
 -import(ordsets, [is_element/2,add_element/2,union/2]).
 -import(orddict, [store/3]).
 
@@ -251,10 +250,10 @@ is_filename(T) ->
 
 shorten_filename(Name0) ->
     {ok,Cwd} = file:get_cwd(),
-    case lists:prefix(Cwd, Name0) of
-        false -> Name0;
-        true ->
-            case lists:nthtail(length(Cwd), Name0) of
+    case string:prefix(Name0, Cwd) of
+        nomatch -> Name0;
+        Rest ->
+            case unicode:characters_to_list(Rest) of
                 "/"++N -> N;
                 N -> N
             end
@@ -490,12 +489,9 @@ parse_rules_end(_, NextLine, REAs, As, St) ->
 %% action has been read. Keep track of line number.
 
 collect_rule(Ifile, Chars, L0) ->
-    %% Erlang strings are 1 based, but re 0 :-(
-    {match,[{St0,Len}|_]} = re:run(Chars, "[^ \t\r\n]+", [unicode]),
-    St = St0 + 1,
-    %%io:fwrite("RE = ~p~n", [substr(Chars, St, Len)]),
-    case collect_action(Ifile, substr(Chars, St+Len), L0, []) of
-        {ok,[{':',_}|Toks],L1} -> {ok,substr(Chars, St, Len),Toks,L1};
+    {RegExp,Rest} = string:take(Chars, " \t\r\n", true),
+    case collect_action(Ifile, Rest, L0, []) of
+        {ok,[{':',_}|Toks],L1} -> {ok,RegExp,Toks,L1};
         {ok,_,_} -> {error,{L0,leex,bad_rule}};
         {eof,L1} -> {error,{L1,leex,bad_rule}};
         {error,E,_} -> {error,E}
@@ -549,7 +545,7 @@ var_used(Name, Toks) ->
 
 parse_rule_regexp(RE0, [{M,Exp}|Ms], St) ->
     Split= re:split(RE0, "\\{" ++ M ++ "\\}", [{return,list},unicode]),
-    RE1 = string:join(Split, Exp),
+    RE1 = lists:append(lists:join(Exp, Split)),
     parse_rule_regexp(RE1, Ms, St);
 parse_rule_regexp(RE, [], St) ->
     %%io:fwrite("RE = ~p~n", [RE]),
@@ -589,9 +585,9 @@ nextline(Ifile, L, St) ->
         eof -> {eof,L};
         {error, _} -> add_error({L+1, leex, cannot_parse}, St);
         Chars ->
-            case substr(Chars, span(Chars, " \t\n")+1) of
-                [$%|_Rest] -> nextline(Ifile, L+1, St);
-                [] -> nextline(Ifile, L+1, St);
+            case string:take(Chars, " \t\n") of
+                {_, [$%|_Rest]} -> nextline(Ifile, L+1, St);
+                {_, []} -> nextline(Ifile, L+1, St);
                 _Other -> {ok,Chars,L+1}
             end
     end.
@@ -824,7 +820,7 @@ re_char_class(Cs, Cc, _) -> {reverse(Cc),Cs}.   % Preserve order
 %% posix_cc("space" ++ Cs) -> {space,Cs};
 %% posix_cc("upper" ++ Cs) -> {upper,Cs};
 %% posix_cc("xdigit" ++ Cs) -> {xdigit,Cs};
-%% posix_cc(Cs) -> parse_error({posix_cc,substr(Cs, 1, 5)}).
+%% posix_cc(Cs) -> parse_error({posix_cc,string:slice(Cs, 0, 5)}).
 
 escape_char($n) -> $\n;                         % \n = LF
 escape_char($r) -> $\r;                         % \r = CR
@@ -863,7 +859,7 @@ escape_char(C) -> C.                            % Pass it straight through
 %% re_number(Cs, Acc) -> {Acc,Cs}.
 
 string_between(Cs1, Cs2) ->
-    substr(Cs1, 1, length(Cs1)-length(Cs2)).
+    string:slice(Cs1, 0, string:length(Cs1)-string:length(Cs2)).
 
 %% We use standard methods, Thompson's construction and subset
 %% construction, to create first an NFA and then a DFA from the
@@ -1343,7 +1339,7 @@ out_file(Ifile, Ofile, St, DFA, DF, Actions, Code, L) ->
         eof -> output_file_directive(Ofile, St#leex.ifile, L);
         {error, _} -> add_error(St#leex.ifile, {L, leex, cannot_parse}, St);
         Line ->
-            case substr(Line, 1, 5) of
+            case string:slice(Line, 0, 5) of
                 "##mod" -> out_module(Ofile, St);
                 "##cod" -> out_erlang_code(Ofile, St, Code, L);
                 "##dfa" -> out_dfa(Ofile, St, DFA, Code, DF, L);
@@ -1523,7 +1519,7 @@ prep_out_actions(As) ->
                 Name = list_to_atom(lists:concat([yyaction_,A])),
                 [Chars,Len,Line,_,_] = Vars,
                 Args = [V || V <- [Chars,Len,Line], V =/= "_"],
-                ArgsChars = string:join(Args, ", "),
+                ArgsChars = lists:join(", ", Args),
                 {A,Code,Vars,Name,Args,ArgsChars}
         end, As).
 
diff --git a/lib/parsetools/src/yecc.erl b/lib/parsetools/src/yecc.erl
index 36e33b52a4..b4e1cfe5e3 100644
--- a/lib/parsetools/src/yecc.erl
+++ b/lib/parsetools/src/yecc.erl
@@ -365,10 +365,10 @@ is_filename(T) ->
 
 shorten_filename(Name0) ->
     {ok,Cwd} = file:get_cwd(),
-    case lists:prefix(Cwd, Name0) of
-        false -> Name0;
-        true ->
-            case lists:nthtail(length(Cwd), Name0) of
+    case string:prefix(Name0, Cwd) of
+        nomatch -> Name0;
+        Rest ->
+            case unicode:characters_to_list(Rest) of
                 "/"++N -> N;
                 N -> N
             end
@@ -2196,8 +2196,8 @@ output_reduce(St0, State, Terminal,
                 St20;
             true ->
                 Ns = "Nss",
-                Tmp = string:join(lists:duplicate(NmbrOfDaughters - 1, "_"),
-                                  ","),
+                Tmp = lists:join(",",
+                                  lists:duplicate(NmbrOfDaughters - 1, "_")),
                 fwrite(St20, <<" [~s|Nss] = Ss,\n">>, [Tmp])
         end,
     St40 = case tokens(RuleNmbr, St30) of
diff --git a/lib/reltool/src/reltool_mod_win.erl b/lib/reltool/src/reltool_mod_win.erl
index 894d6e2ecb..dcd802a5de 100644
--- a/lib/reltool/src/reltool_mod_win.erl
+++ b/lib/reltool/src/reltool_mod_win.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2009-2016. All Rights Reserved.
+%% Copyright Ericsson AB 2009-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
diff --git a/lib/reltool/src/reltool_target.erl b/lib/reltool/src/reltool_target.erl
index 1b1461178e..676ce70aea 100644
--- a/lib/reltool/src/reltool_target.erl
+++ b/lib/reltool/src/reltool_target.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2009-2016. All Rights Reserved.
+%% Copyright Ericsson AB 2009-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
diff --git a/lib/reltool/src/reltool_utils.erl b/lib/reltool/src/reltool_utils.erl
index 3891b5ae4d..1a00671f13 100644
--- a/lib/reltool/src/reltool_utils.erl
+++ b/lib/reltool/src/reltool_utils.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 2009-2016. All Rights Reserved.
+%% Copyright Ericsson AB 2009-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
diff --git a/lib/reltool/test/reltool_server_SUITE.erl b/lib/reltool/test/reltool_server_SUITE.erl
index e8dfea94da..e97b23efe2 100644
--- a/lib/reltool/test/reltool_server_SUITE.erl
+++ b/lib/reltool/test/reltool_server_SUITE.erl
@@ -2549,7 +2549,7 @@ undefined_regexp(_Config) ->
 %% Library functions
 
 erl_libs() ->
-    string:tokens(os:getenv("ERL_LIBS", ""), ":;").
+    string:lexemes(os:getenv("ERL_LIBS", ""), ":;").
 
 datadir(Config) ->
     %% Removes the trailing slash...
@@ -2559,7 +2559,7 @@ latest(App) ->
     AppStr = atom_to_list(App),
     AppDirs = filelib:wildcard(filename:join(code:lib_dir(),AppStr++"-*")),
     [LatestAppDir|_] = lists:reverse(AppDirs),
-    [_,Vsn] = string:tokens(filename:basename(LatestAppDir),"-"),
+    [_,Vsn] = string:lexemes(filename:basename(LatestAppDir),"-"),
     Vsn.
 
 rm_missing_app(Apps) ->
@@ -2635,16 +2635,11 @@ os_cmd(Cmd) when is_list(Cmd) ->
         Return->
             %% Find the position of the status code wich is last in the string
             %% prepended with #
-            case string:rchr(Return, $#) of
-                
-                %% This happens only if the sh command pipe is somehow interrupted
-                0->
-                {98, Return};
-                
-                Position->
-                Result = string:left(Return,Position - 1),
-                Status = string:substr(Return,Position + 1, length(Return) - Position - 1),
-                {list_to_integer(Status), Result}
+            case string:split(Return, "$#", trailing) of
+                [_] -> %% This happens only if the sh command pipe is somehow interrupted
+                    {98, Return};
+                [Result, Status0] ->
+                    {list_to_integer(string:trim(Status0)), Result}
             end
     end.
 
diff --git a/lib/runtime_tools/src/erts_alloc_config.erl b/lib/runtime_tools/src/erts_alloc_config.erl
index 514530332c..342363d08d 100644
--- a/lib/runtime_tools/src/erts_alloc_config.erl
+++ b/lib/runtime_tools/src/erts_alloc_config.erl
@@ -621,7 +621,7 @@ format_header(FTO) ->
 	[Y, Mo, D, H, Mi, S]),
     fcp(FTO,
 	"~s was used when generating the configuration.",
-	[string:strip(erlang:system_info(system_version), both, $\n)]),
+	[string:trim(erlang:system_info(system_version), both, "$\n")]),
     case erlang:system_info(schedulers) of
 	1 -> ok;
 	Schdlrs ->
@@ -698,28 +698,32 @@ fc(IODev, Frmt, Args) ->
     fc(IODev, lists:flatten(io_lib:format(Frmt, Args))).
 
 fc(IODev, String) ->
-    fc_aux(IODev, string:tokens(String, " "), 0).
+    fc_aux(IODev, string:lexemes(String, " "), 0).
 
 fc_aux(_IODev, [], 0) ->
     ok;
 fc_aux(IODev, [], _Len) ->
     format(IODev, "~n");
 fc_aux(IODev, [T|Ts], 0) ->
-    Len = 2 + length(T),
+    Len = 2 + string:length(T),
     format(IODev, "# ~s", [T]),
     fc_aux(IODev, Ts, Len);
-fc_aux(IODev, [T|_Ts] = ATs, Len) when (length(T) + Len) >= ?PRINT_WITDH ->
-    format(IODev, "~n"),
-    fc_aux(IODev, ATs, 0);
-fc_aux(IODev, [T|Ts], Len) ->
-    NewLen = Len + 1 + length(T),
-    format(IODev, " ~s", [T]),
-    fc_aux(IODev, Ts, NewLen).
+fc_aux(IODev, [T|Ts] = ATs, Len) ->
+    TLength = string:length(T),
+    case (TLength + Len) >= ?PRINT_WITDH of
+        true ->
+            format(IODev, "~n"),
+            fc_aux(IODev, ATs, 0);
+        false ->
+            NewLen = Len + 1 + TLength,
+            format(IODev, " ~s", [T]),
+            fc_aux(IODev, Ts, NewLen)
+    end.
 
 %% fcl: format comment line
 fcl(FTO) ->
     EndStr = "# ",
-    Precision = length(EndStr),
+    Precision = string:length(EndStr),
     FieldWidth = -1*(?PRINT_WITDH),
     format(FTO, "~*.*.*s~n", [FieldWidth, Precision, $-, EndStr]).
 
@@ -727,6 +731,6 @@ fcl(FTO, A) when is_atom(A) ->
     fcl(FTO, atom_to_list(A));
 fcl(FTO, Str) when is_list(Str) ->
     Str2 = "# --- " ++ Str ++ " ",
-    Precision = length(Str2),
+    Precision = string:length(Str2),
     FieldWidth = -1*(?PRINT_WITDH),
     format(FTO, "~*.*.*s~n", [FieldWidth, Precision, $-, Str2]).
diff --git a/lib/runtime_tools/src/system_information.erl b/lib/runtime_tools/src/system_information.erl
index df25297eb9..92109c9a74 100644
--- a/lib/runtime_tools/src/system_information.erl
+++ b/lib/runtime_tools/src/system_information.erl
@@ -590,12 +590,12 @@ vsnstr2vsn(VsnStr) ->
     list_to_tuple(lists:map(fun (Part) ->
 				    list_to_integer(Part)
 			    end,
-			    string:tokens(VsnStr, "."))).
+			    string:lexemes(VsnStr, "."))).
 
 rtdepstrs2rtdeps([]) ->
     [];
 rtdepstrs2rtdeps([RTDep | RTDeps]) ->
-    [AppStr, VsnStr] = string:tokens(RTDep, "-"),
+    [AppStr, VsnStr] = string:lexemes(RTDep, "-"),
     [{list_to_atom(AppStr), vsnstr2vsn(VsnStr)} | rtdepstrs2rtdeps(RTDeps)].
 
 build_app_table([], AppTab) ->
diff --git a/lib/sasl/src/erlsrv.erl b/lib/sasl/src/erlsrv.erl
index 29d40d362f..e0bbd37ee3 100644
--- a/lib/sasl/src/erlsrv.erl
+++ b/lib/sasl/src/erlsrv.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %% 
-%% Copyright Ericsson AB 1998-2016. All Rights Reserved.
+%% Copyright Ericsson AB 1998-2017. All Rights Reserved.
 %% 
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -34,7 +34,7 @@ erlsrv(EVer) ->
     filename:join([Root, "erts-" ++ EVer, "bin", "erlsrv.exe"]).
 
 current_version() ->
-    hd(string:tokens(erlang:system_info(version),"_ ")).
+    hd(string:lexemes(erlang:system_info(version),"_ ")).
 
 %%% Returns {ok, Output} | failed | {error, Reason}
 run_erlsrv(Command) ->
@@ -107,7 +107,7 @@ get_all_services() ->
 	    [];
 	{ok, [_H|T]} ->
 	    F = fun(X) ->
-			hd(string:tokens(X,"\t "))
+			hd(string:lexemes(X,"\t "))
 		end,
 	    lists:map(F,T);
 	_ ->
@@ -191,8 +191,8 @@ get_service(EVer, ServiceName) ->
 	    %%% have in the environment list...
 	    EnvParts = lists:map(
 			 fun(S) ->
-				 X = string:strip(S,left,$\t),
-				 case hd(string:tokens(X,"=")) of
+				 X = string:trim(S, leading, "$\t"),
+				 case hd(string:lexemes(X,"=")) of
 				     X ->
 					 %% Can this happen?
 					 {X,""};
@@ -371,7 +371,7 @@ split_arglist([H|T]) ->
 parse_arglist(Str) ->
     lists:reverse(parse_arglist(Str,[])).
 parse_arglist(Str,Accum) ->
-    Stripped = string:strip(Str,left),
+    Stripped = string:trim(Str, leading),
     case length(Stripped) of
 	0 ->
 	    Accum;
@@ -432,14 +432,9 @@ split_by_env(Data) ->
 			
 
 splitline(Line) ->
-    case string:chr(Line,$:) of
-	0 ->
+    case string:split(Line, ":") of
+        [_] ->
 	    {Line, ""};
-	N ->
-	    case length(string:substr(Line,N)) of
-		1 ->
-		    {string:substr(Line,1,N-1),""};
-		_ ->
-		    {string:substr(Line,1,N-1),string:substr(Line,N+2)}
-	    end
+        [N, V] ->
+            {N, string:slice(V, 1)}
     end.
diff --git a/lib/sasl/src/format_lib_supp.erl b/lib/sasl/src/format_lib_supp.erl
index 80dcdc91da..cfe2ec7668 100644
--- a/lib/sasl/src/format_lib_supp.erl
+++ b/lib/sasl/src/format_lib_supp.erl
@@ -100,13 +100,13 @@ print_newlines(Device, N) when N > 0 ->
 print_one_line(Device, Line, Key, Value) ->
     Modifier = misc_supp:modifier(Device),
     StrKey = term_to_string(Key,Modifier),
-    KeyLen = lists:min([length(StrKey), Line]),
+    KeyLen = lists:min([string:length(StrKey), Line]),
     ValueLen = Line - KeyLen,
     Format1 = lists:concat(["~-", KeyLen, Modifier, "s"]),
     Format2 = lists:concat(["~", ValueLen, Modifier, "s~n"]),
     io:format(Device, Format1, [StrKey]),
     Try = term_to_string(Value,Modifier),
-    Length = length(Try),
+    Length = string:length(Try),
     if
 	Length < ValueLen ->
 	    io:format(Device, Format2, [Try]);
@@ -117,7 +117,7 @@ print_one_line(Device, Line, Key, Value) ->
     end.
 
 term_to_string(Value,Modifier) ->
-    lists:flatten(io_lib:format(get_format(Value,Modifier), [Value])).
+    io_lib:format(get_format(Value,Modifier), [Value]).
 
 get_format([],_) ->
     "~p";
diff --git a/lib/sasl/src/rb.erl b/lib/sasl/src/rb.erl
index 6595d29a9c..28829132a1 100644
--- a/lib/sasl/src/rb.erl
+++ b/lib/sasl/src/rb.erl
@@ -586,14 +586,14 @@ find_widths([], _Modifier, DescrWidth, DateWidth, Data) ->
     {DescrWidth+1, DateWidth+1, lists:reverse(Data)};
 find_widths([H|T], Modifier, DescrWidth, DateWidth, Data) ->
     DescrTerm = element(3,H),
-    Descr = lists:flatten(io_lib:format("~"++Modifier++"w", [DescrTerm])),
-    DescrTry = length(Descr),
+    Descr = io_lib:format("~"++Modifier++"w", [DescrTerm]),
+    DescrTry = string:length(Descr),
     NewDescrWidth =
         if
             DescrTry > DescrWidth -> DescrTry;
             true -> DescrWidth
         end,
-    DateTry = length(element(4, H)),
+    DateTry = string:length(element(4, H)),
     NewDateWitdh =
         if
             DateTry > DateWidth -> DateTry;
diff --git a/lib/sasl/src/rb_format_supp.erl b/lib/sasl/src/rb_format_supp.erl
index 1eda43dae4..b5b7aba151 100644
--- a/lib/sasl/src/rb_format_supp.erl
+++ b/lib/sasl/src/rb_format_supp.erl
@@ -108,7 +108,7 @@ print(Date, Report, Device) ->
 
 format_h(Line, Header, Pid, Date) ->
     NHeader = lists:flatten(io_lib:format("~s  ~w", [Header, Pid])), 
-    DateLen = length(Date),
+    DateLen = string:length(Date),
     HeaderLen = Line - DateLen,
     Format = lists:concat(["~-", HeaderLen, "s~", DateLen, "s"]),
     io_lib:format(Format, [NHeader, Date]).
diff --git a/lib/sasl/src/release_handler.erl b/lib/sasl/src/release_handler.erl
index d0a7c7332d..bfa49fc05d 100644
--- a/lib/sasl/src/release_handler.erl
+++ b/lib/sasl/src/release_handler.erl
@@ -420,7 +420,7 @@ upgrade_app(App, NewDir) ->
 %%          located in the ebin dir of the _current_ version
 %%-----------------------------------------------------------------
 downgrade_app(App, OldDir) ->
-    case string:tokens(filename:basename(OldDir), "-") of
+    case string:lexemes(filename:basename(OldDir), "-") of
 	[_AppS, OldVsn] ->
 	    downgrade_app(App, OldVsn, OldDir);
 	_ ->
@@ -1174,8 +1174,8 @@ new_emulator_rm_tmp_release(_,_,_,_,Releases,_) ->
 
 %% Rename the tempoarary service (for erts ugprade) to the real ToVsn
 rename_tmp_service(EVsn,TmpVsn,NewVsn) ->
-    FromName = hd(string:tokens(atom_to_list(node()),"@")) ++ "_" ++ TmpVsn,
-    ToName = hd(string:tokens(atom_to_list(node()),"@")) ++ "_" ++ NewVsn,
+    FromName = hd(string:lexemes(atom_to_list(node()),"@")) ++ "_" ++ TmpVsn,
+    ToName = hd(string:lexemes(atom_to_list(node()),"@")) ++ "_" ++ NewVsn,
     case erlsrv:get_service(EVsn,ToName) of
 	{error, _Error} ->
 	    ok;
@@ -1207,9 +1207,9 @@ rename_service(EVsn,FromName,ToName) ->
 %%% in which case we try to rename the old service to the new name and try
 %%% to update heart's view of what service we are really running.
 do_make_services_permanent(PermanentVsn,Vsn, PermanentEVsn, EVsn) ->
-    PermName = hd(string:tokens(atom_to_list(node()),"@")) 
+    PermName = hd(string:lexemes(atom_to_list(node()),"@"))
 	++ "_" ++ PermanentVsn,
-    Name = hd(string:tokens(atom_to_list(node()),"@")) 
+    Name = hd(string:lexemes(atom_to_list(node()),"@"))
 	++ "_" ++ Vsn,
     case erlsrv:get_service(EVsn,Name) of
 	{error, _Error} ->
@@ -1296,7 +1296,7 @@ do_make_permanent(#state{releases = Releases,
 
 
 do_back_service(OldVersion, CurrentVersion,OldEVsn,CurrentEVsn) ->
-    NN = hd(string:tokens(atom_to_list(node()),"@")),
+    NN = hd(string:lexemes(atom_to_list(node()),"@")),
     OldName = NN ++ "_" ++ OldVersion,
     CurrentName = NN ++ "_" ++ CurrentVersion,
     UpdData = case erlsrv:get_service(CurrentEVsn,CurrentName) of
@@ -1385,7 +1385,7 @@ do_remove_service(Vsn) ->
     %% Very unconditionally remove the service.
     %% Note that the service could already have been removed when
     %% making another release permanent.
-    ServiceName = hd(string:tokens(atom_to_list(node()),"@")) 
+    ServiceName = hd(string:lexemes(atom_to_list(node()),"@"))
 	++ "_" ++ Vsn,
     case erlsrv:get_service(ServiceName) of
 	{error, _Error} ->
@@ -1670,9 +1670,9 @@ flush() ->
 prepare_restart_nt(#release{erts_vsn = EVsn, vsn = Vsn},
 		   #release{erts_vsn = PermEVsn, vsn = PermVsn},
 		   DataFileName) ->
-    CurrentServiceName = hd(string:tokens(atom_to_list(node()),"@")) 
+    CurrentServiceName = hd(string:lexemes(atom_to_list(node()),"@"))
 	++ "_" ++ PermVsn,
-    FutureServiceName = hd(string:tokens(atom_to_list(node()),"@")) 
+    FutureServiceName = hd(string:lexemes(atom_to_list(node()),"@"))
 	++ "_" ++ Vsn,
     CurrentService = case erlsrv:get_service(PermEVsn,CurrentServiceName) of
 			 {error, _} = Error1 ->
diff --git a/lib/stdlib/doc/src/string.xml b/lib/stdlib/doc/src/string.xml
index 9d5edd9ecf..130fc74a28 100644
--- a/lib/stdlib/doc/src/string.xml
+++ b/lib/stdlib/doc/src/string.xml
@@ -109,10 +109,8 @@
     <p>This module has been reworked in Erlang/OTP 20 to
     handle <seealso marker="unicode#type-chardata">
     <c>unicode:chardata()</c></seealso> and operate on grapheme
-    clusters. The <seealso marker="#oldapi"> <c>old
-    functions</c></seealso> that only work on Latin-1 lists as input
-    are still available but should not be
-    used. They will be deprecated in Erlang/OTP 21.
+    clusters. The <c>old functions</c> that only work on Latin-1 lists as input
+    are kept for backwards compatibility reasons but should not be used.
     </p>
   </description>
 
@@ -594,7 +592,7 @@ ÖÄÅ</pre>
 	  or <c>both</c>, indicates from which direction characters
 	  are to be removed.
 	</p>
-	<p> Default <c><anno>Characters</anno></c> are the set of
+	<p> Default <c><anno>Characters</anno></c> is the set of
 	nonbreakable whitespace codepoints, defined as
 	Pattern_White_Space in
 	<url href="http://unicode.org/reports/tr31/">Unicode Standard Annex #31</url>.
@@ -631,393 +629,5 @@ ÖÄÅ</pre>
     </func>
 
   </funcs>
-
-  <section>
-    <marker id="oldapi"/>
-    <title>Obsolete API functions</title>
-    <p>Here follows the function of the old API.
-    These functions only work on a list of Latin-1 characters.
-    </p>
-    <note><p>
-      The functions are kept for backward compatibility, but are
-      not recommended.
-      They will be deprecated in Erlang/OTP 21.
-    </p>
-    <p>Any undocumented functions in <c>string</c> are not to be used.</p>
-    </note>
-  </section>
-
-  <funcs>
-    <func>
-      <name name="centre" arity="2"/>
-      <name name="centre" arity="3"/>
-      <fsummary>Center a string.</fsummary>
-      <desc>
-        <p>Returns a string, where <c><anno>String</anno></c> is centered in the
-          string and surrounded by blanks or <c><anno>Character</anno></c>.
-	  The resulting string has length <c><anno>Number</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#pad/3"><c>pad/3</c></seealso>.
-	</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="chars" arity="2"/>
-      <name name="chars" arity="3"/>
-      <fsummary>Return a string consisting of numbers of characters.</fsummary>
-      <desc>
-        <p>Returns a string consisting of <c><anno>Number</anno></c> characters
-          <c><anno>Character</anno></c>. Optionally, the string can end with
-          string <c><anno>Tail</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="lists#duplicate/2"><c>lists:duplicate/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="chr" arity="2"/>
-      <fsummary>Return the index of the first occurrence of
-        a character in a string.</fsummary>
-      <desc>
-        <p>Returns the index of the first occurrence of
-          <c><anno>Character</anno></c> in <c><anno>String</anno></c>. Returns
-          <c>0</c> if <c><anno>Character</anno></c> does not occur.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/2"><c>find/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="concat" arity="2"/>
-      <fsummary>Concatenate two strings.</fsummary>
-      <desc>
-        <p>Concatenates <c><anno>String1</anno></c> and
-          <c><anno>String2</anno></c> to form a new string
-          <c><anno>String3</anno></c>, which is returned.</p>
-	<p>
-	  This function is <seealso marker="#oldapi">obsolete</seealso>.
-	  Use <c>[<anno>String1</anno>, <anno>String2</anno>]</c> as
-	  <c>Data</c> argument, and call
-	  <seealso marker="unicode#characters_to_list/2">
-	  <c>unicode:characters_to_list/2</c></seealso> or
-	  <seealso marker="unicode#characters_to_binary/2">
-	  <c>unicode:characters_to_binary/2</c></seealso>
-	  to flatten the output.
-	</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="copies" arity="2"/>
-      <fsummary>Copy a string.</fsummary>
-      <desc>
-        <p>Returns a string containing <c><anno>String</anno></c> repeated
-          <c><anno>Number</anno></c> times.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="lists#duplicate/2"><c>lists:duplicate/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="cspan" arity="2"/>
-      <fsummary>Span characters at start of a string.</fsummary>
-      <desc>
-        <p>Returns the length of the maximum initial segment of
-          <c><anno>String</anno></c>, which consists entirely of characters
-          not from <c><anno>Chars</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#take/3"><c>take/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:cspan("\t    abcdef", " \t").
-0</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="join" arity="2"/>
-      <fsummary>Join a list of strings with separator.</fsummary>
-      <desc>
-        <p>Returns a string with the elements of <c><anno>StringList</anno></c>
-          separated by the string in <c><anno>Separator</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="lists#join/2"><c>lists:join/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> join(["one", "two", "three"], ", ").
-"one, two, three"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="left" arity="2"/>
-      <name name="left" arity="3"/>
-      <fsummary>Adjust left end of a string.</fsummary>
-      <desc>
-        <p>Returns <c><anno>String</anno></c> with the length adjusted in
-          accordance with <c><anno>Number</anno></c>. The left margin is
-          fixed. If <c>length(<anno>String</anno>)</c> &lt;
-          <c><anno>Number</anno></c>, then <c><anno>String</anno></c> is padded
-          with blanks or <c><anno>Character</anno></c>s.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#pad/2"><c>pad/2</c></seealso> or
-	<seealso marker="#pad/3"><c>pad/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:left("Hello",10,$.).
-"Hello....."</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="len" arity="1"/>
-      <fsummary>Return the length of a string.</fsummary>
-      <desc>
-        <p>Returns the number of characters in <c><anno>String</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#length/1"><c>length/1</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="rchr" arity="2"/>
-      <fsummary>Return the index of the last occurrence of
-        a character in a string.</fsummary>
-      <desc>
-        <p>Returns the index of the last occurrence of
-          <c><anno>Character</anno></c> in <c><anno>String</anno></c>. Returns
-          <c>0</c> if <c><anno>Character</anno></c> does not occur.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/3"><c>find/3</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="right" arity="2"/>
-      <name name="right" arity="3"/>
-      <fsummary>Adjust right end of a string.</fsummary>
-      <desc>
-        <p>Returns <c><anno>String</anno></c> with the length adjusted in
-          accordance with <c><anno>Number</anno></c>. The right margin is
-          fixed. If the length of <c>(<anno>String</anno>)</c> &lt;
-          <c><anno>Number</anno></c>, then <c><anno>String</anno></c> is padded
-          with blanks or <c><anno>Character</anno></c>s.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#pad/3"><c>pad/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:right("Hello", 10, $.).
-".....Hello"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="rstr" arity="2"/>
-      <fsummary>Find the index of a substring.</fsummary>
-      <desc>
-        <p>Returns the position where the last occurrence of
-          <c><anno>SubString</anno></c> begins in <c><anno>String</anno></c>.
-          Returns <c>0</c> if <c><anno>SubString</anno></c>
-          does not exist in <c><anno>String</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/3"><c>find/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:rstr(" Hello Hello World World ", "Hello World").
-8</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="span" arity="2"/>
-      <fsummary>Span characters at start of a string.</fsummary>
-      <desc>
-        <p>Returns the length of the maximum initial segment of
-          <c><anno>String</anno></c>, which consists entirely of characters
-          from <c><anno>Chars</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#take/2"><c>take/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:span("\t    abcdef", " \t").
-5</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="str" arity="2"/>
-      <fsummary>Find the index of a substring.</fsummary>
-      <desc>
-        <p>Returns the position where the first occurrence of
-          <c><anno>SubString</anno></c> begins in <c><anno>String</anno></c>.
-          Returns <c>0</c> if <c><anno>SubString</anno></c>
-          does not exist in <c><anno>String</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#find/2"><c>find/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:str(" Hello Hello World World ", "Hello World").
-8</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="strip" arity="1"/>
-      <name name="strip" arity="2"/>
-      <name name="strip" arity="3"/>
-      <fsummary>Strip leading or trailing characters.</fsummary>
-      <desc>
-        <p>Returns a string, where leading or trailing, or both, blanks or a
-          number of <c><anno>Character</anno></c> have been removed.
-          <c><anno>Direction</anno></c>, which can be <c>left</c>, <c>right</c>,
-          or <c>both</c>, indicates from which direction blanks are to be
-          removed. <c>strip/1</c> is equivalent to
-          <c>strip(String, both)</c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#trim/3"><c>trim/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:strip("...Hello.....", both, $.).
-"Hello"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="sub_string" arity="2"/>
-      <name name="sub_string" arity="3"/>
-      <fsummary>Extract a substring.</fsummary>
-      <desc>
-        <p>Returns a substring of <c><anno>String</anno></c>, starting at
-          position <c><anno>Start</anno></c> to the end of the string, or to
-          and including position <c><anno>Stop</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#slice/3"><c>slice/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-sub_string("Hello World", 4, 8).
-"lo Wo"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="substr" arity="2"/>
-      <name name="substr" arity="3"/>
-      <fsummary>Return a substring of a string.</fsummary>
-      <desc>
-        <p>Returns a substring of <c><anno>String</anno></c>, starting at
-          position <c><anno>Start</anno></c>, and ending at the end of the
-          string or at length <c><anno>Length</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#slice/3"><c>slice/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> substr("Hello World", 4, 5).
-"lo Wo"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="sub_word" arity="2"/>
-      <name name="sub_word" arity="3"/>
-      <fsummary>Extract subword.</fsummary>
-      <desc>
-        <p>Returns the word in position <c><anno>Number</anno></c> of
-          <c><anno>String</anno></c>. Words are separated by blanks or
-          <c><anno>Character</anno></c>s.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#nth_lexeme/3"><c>nth_lexeme/3</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> string:sub_word(" Hello old boy !",3,$o).
-"ld b"</code>
-      </desc>
-    </func>
-
-    <func>
-      <name name="to_lower" arity="1" clause_i="1"/>
-      <name name="to_lower" arity="1" clause_i="2"/>
-      <name name="to_upper" arity="1" clause_i="1"/>
-      <name name="to_upper" arity="1" clause_i="2"/>
-      <fsummary>Convert case of string (ISO/IEC 8859-1).</fsummary>
-      <type variable="String" name_i="1"/>
-      <type variable="Result" name_i="1"/>
-      <type variable="Char"/>
-      <type variable="CharResult"/>
-      <desc>
-        <p>The specified string or character is case-converted. Notice that
-          the supported character set is ISO/IEC 8859-1 (also called Latin 1);
-          all values outside this set are unchanged</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso> use
-	<seealso marker="#lowercase/1"><c>lowercase/1</c></seealso>,
-	<seealso marker="#uppercase/1"><c>uppercase/1</c></seealso>,
-	<seealso marker="#titlecase/1"><c>titlecase/1</c></seealso> or
-	<seealso marker="#casefold/1"><c>casefold/1</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="tokens" arity="2"/>
-      <fsummary>Split string into tokens.</fsummary>
-      <desc>
-        <p>Returns a list of tokens in <c><anno>String</anno></c>, separated
-          by the characters in <c><anno>SeparatorList</anno></c>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> tokens("abc defxxghix jkl", "x ").
-["abc", "def", "ghi", "jkl"]</code>
-        <p>Notice that, as shown in this example, two or more
-          adjacent separator characters in <c><anno>String</anno></c>
-          are treated as one. That is, there are no empty
-          strings in the resulting list of tokens.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#lexemes/2"><c>lexemes/2</c></seealso>.</p>
-      </desc>
-    </func>
-
-    <func>
-      <name name="words" arity="1"/>
-      <name name="words" arity="2"/>
-      <fsummary>Count blank separated words.</fsummary>
-      <desc>
-        <p>Returns the number of words in <c><anno>String</anno></c>, separated
-          by blanks or <c><anno>Character</anno></c>.</p>
-	<p>This function is <seealso marker="#oldapi">obsolete</seealso>.
-	Use
-	<seealso marker="#lexemes/2"><c>lexemes/2</c></seealso>.</p>
-        <p><em>Example:</em></p>
-        <code type="none">
-> words(" Hello old boy!", $o).
-4</code>
-      </desc>
-    </func>
-  </funcs>
-
-  <section>
-    <title>Notes</title>
-    <p>Some of the general string functions can seem to overlap each
-      other. The reason is that this string package is the
-      combination of two earlier packages and all functions of
-      both packages have been retained.</p>
-  </section>
-
 </erlref>
 
diff --git a/lib/stdlib/src/epp.erl b/lib/stdlib/src/epp.erl
index 31d0d499e3..00e6a10d8a 100644
--- a/lib/stdlib/src/epp.erl
+++ b/lib/stdlib/src/epp.erl
@@ -479,7 +479,7 @@ com_enc(_B, _Fun, _N, L, Ps) ->
     com_enc_end([L | Ps]).
 
 com_enc_end(Ps0) ->
-    Ps = lists:reverse([lists:reverse(string:to_lower(P)) || P <- Ps0]),
+    Ps = lists:reverse([lists:reverse(lowercase(P)) || P <- Ps0]),
     com_encoding(Ps).
 
 com_encoding(["latin","1"|_]) ->
@@ -489,6 +489,9 @@ com_encoding(["utf","8"|_]) ->
 com_encoding(_) ->
     throw(no). % Don't try any further
 
+lowercase(S) ->
+    unicode:characters_to_list(string:lowercase(S)).
+
 normalize_typed_record_fields([]) ->
     {typed, []};
 normalize_typed_record_fields(Fields) ->
diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl
index 9cd4727dc3..f58cb35cea 100644
--- a/lib/stdlib/src/erl_lint.erl
+++ b/lib/stdlib/src/erl_lint.erl
@@ -3910,10 +3910,9 @@ check_format_string(Fmt) ->
     extract_sequences(Fmt, []).
 
 extract_sequences(Fmt, Need0) ->
-    case string:chr(Fmt, $~) of
-        0 -> {ok,lists:reverse(Need0)};         %That's it
-        Pos ->
-            Fmt1 = string:substr(Fmt, Pos+1),   %Skip ~
+    case string:find(Fmt, [$~]) of
+        nomatch -> {ok,lists:reverse(Need0)};         %That's it
+        [$~|Fmt1] ->
             case extract_sequence(1, Fmt1, Need0) of
                 {ok,Need1,Rest} -> extract_sequences(Rest, Need1);
                 Error -> Error
diff --git a/lib/stdlib/src/erl_pp.erl b/lib/stdlib/src/erl_pp.erl
index b0064aadb8..367dbefb82 100644
--- a/lib/stdlib/src/erl_pp.erl
+++ b/lib/stdlib/src/erl_pp.erl
@@ -237,13 +237,20 @@ lform({attribute,Line,Name,Arg}, Opts) ->
 lform({function,Line,Name,Arity,Clauses}, Opts) ->
     lfunction({function,Line,Name,Arity,Clauses}, Opts);
 %% These are specials to make it easier for the compiler.
-lform({error,E}, _Opts) ->
-    leaf(format("~p\n", [{error,E}]));
-lform({warning,W}, _Opts) ->
-    leaf(format("~p\n", [{warning,W}]));
+lform({error,_}=E, Opts) ->
+    message(E, Opts);
+lform({warning,_}=W, Opts) ->
+    message(W, Opts);
 lform({eof,_Line}, _Opts) ->
     $\n.
 
+message(M, #options{encoding = Encoding}) ->
+    F = case Encoding of
+            latin1 -> "~p\n";
+            unicode -> "~tp\n"
+        end,
+    leaf(format(F, [M])).
+
 lattribute({attribute,_Line,type,Type}, Opts) ->
     [typeattr(type, Type, Opts),leaf(".\n")];
 lattribute({attribute,_Line,opaque,Type}, Opts) ->
@@ -902,7 +909,7 @@ maybe_paren(_P, _Prec, Expr) ->
     Expr.
 
 leaf(S) ->
-    {leaf,chars_size(S),S}.
+    {leaf,string:length(S),S}.
 
 %%% Do the formatting. Currently nothing fancy. Could probably have
 %%% done it in one single pass.
@@ -962,7 +969,7 @@ f({seq,Before,After,Sep,LItems}, I0, ST, WT, PP) ->
     Sizes = BSizeL ++ SizeL,
     NSepChars = if
                     is_list(Sep), Sep =/= [] ->
-                        erlang:max(0, length(CharsL)-1);
+                        erlang:max(0, length(CharsL)-1); % not string:length
                     true ->
                         0
                 end,
@@ -1118,7 +1125,7 @@ incr(I, Incr) ->
     I+Incr.
 
 indentation(E, I) when I < 0 ->
-    chars_size(E);
+    string:length(E);
 indentation(E, I0) ->
     I = io_lib_format:indentation(E, I0),
     case has_nl(E) of
@@ -1155,19 +1162,19 @@ write_a_string(S, I, PP) ->
 write_a_string([], _N, _Len, _PP) ->
     [];
 write_a_string(S, N, Len, PP) ->
-    SS = string:sub_string(S, 1, N),
+    SS = string:slice(S, 0, N),
     Sl = write_string(SS, PP),
-    case (chars_size(Sl) > Len) and (N > ?MIN_SUBSTRING) of
+    case (string:length(Sl) > Len) and (N > ?MIN_SUBSTRING) of
         true ->
             write_a_string(S, N-1, Len, PP);
         false ->
             [flat_leaf(Sl) |
-             write_a_string(lists:nthtail(length(SS), S), Len, Len, PP)]
+             write_a_string(string:slice(S, string:length(SS)), Len, Len, PP)]
     end.
 
 flat_leaf(S) ->
     L = lists:flatten(S),
-    {leaf,length(L),L}.
+    {leaf,string:length(L),L}.
 
 write_value(V, PP) ->
     (PP#pp.value_fun)(V).
@@ -1188,15 +1195,6 @@ write_char(C, PP) ->
 a0() ->
     erl_anno:new(0).
 
-chars_size([C | Es]) when is_integer(C) ->
-    1 + chars_size(Es);
-chars_size([E | Es]) ->
-    chars_size(E) + chars_size(Es);
-chars_size([]) ->
-    0;
-chars_size(B) when is_binary(B) ->
-    byte_size(B).
-
 -define(N_SPACES, 30).
 
 spacetab() ->
diff --git a/lib/stdlib/src/erl_scan.erl b/lib/stdlib/src/erl_scan.erl
index 47223b129c..4774c4bf19 100644
--- a/lib/stdlib/src/erl_scan.erl
+++ b/lib/stdlib/src/erl_scan.erl
@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2015. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2017. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -752,7 +752,7 @@ scan_string(Cs, St, Line, Col, Toks, {Wcs,Str,Line0,Col0}) ->
         {char_error,Ncs,Error,Nline,Ncol,EndCol} ->
             scan_error(Error, Nline, Ncol, Nline, EndCol, Ncs);
         {error,Nline,Ncol,Nwcs,Ncs} ->
-            Estr = string:substr(Nwcs, 1, 16), % Expanded escape chars.
+            Estr = string:slice(Nwcs, 0, 16), % Expanded escape chars.
             scan_error({string,$\",Estr}, Line0, Col0, Nline, Ncol, Ncs); %"
         {Ncs,Nline,Ncol,Nstr,Nwcs} ->
             Anno = anno(Line0, Col0, St, Nstr),
@@ -767,7 +767,7 @@ scan_qatom(Cs, St, Line, Col, Toks, {Wcs,Str,Line0,Col0}) ->
         {char_error,Ncs,Error,Nline,Ncol,EndCol} ->
             scan_error(Error, Nline, Ncol, Nline, EndCol, Ncs);
         {error,Nline,Ncol,Nwcs,Ncs} ->
-            Estr = string:substr(Nwcs, 1, 16), % Expanded escape chars.
+            Estr = string:slice(Nwcs, 0, 16), % Expanded escape chars.
             scan_error({string,$\',Estr}, Line0, Col0, Nline, Ncol, Ncs); %'
         {Ncs,Nline,Ncol,Nstr,Nwcs} ->
             case catch list_to_atom(Nwcs) of
diff --git a/lib/stdlib/src/escript.erl b/lib/stdlib/src/escript.erl
index 2b9d8ff65b..132f8efbbe 100644
--- a/lib/stdlib/src/escript.erl
+++ b/lib/stdlib/src/escript.erl
@@ -224,8 +224,8 @@ return_sections(S, Bin) ->
 normalize_section(Name, undefined) ->
     {Name, undefined};
 normalize_section(shebang, "#!" ++ Chars) ->
-    Chopped = string:strip(Chars, right, $\n),
-    Stripped = string:strip(Chopped, both),
+    Chopped = string:trim(Chars, trailing, "$\n"),
+    Stripped = string:trim(Chopped, both),
     if
 	Stripped =:= ?SHEBANG ->
 	    {shebang, default};
@@ -233,8 +233,8 @@ normalize_section(shebang, "#!" ++ Chars) ->
 	    {shebang, Stripped}
     end;
 normalize_section(comment, Chars) ->
-    Chopped = string:strip(Chars, right, $\n),
-    Stripped = string:strip(string:strip(Chopped, left, $%), both),
+    Chopped = string:trim(Chars, trailing, "$\n"),
+    Stripped = string:trim(string:trim(Chopped, leading, "$%"), both),
     if
 	Stripped =:= ?COMMENT ->
 	    {comment, default};
@@ -242,8 +242,8 @@ normalize_section(comment, Chars) ->
 	    {comment, Stripped}
     end;
 normalize_section(emu_args, "%%!" ++ Chars) ->
-    Chopped = string:strip(Chars, right, $\n),
-    Stripped = string:strip(Chopped, both),
+    Chopped = string:trim(Chars, trailing, "$\n"),
+    Stripped = string:trim(Chopped, both),
     {emu_args, Stripped};
 normalize_section(Name, Chars) ->
     {Name, Chars}.
diff --git a/lib/stdlib/src/ets.erl b/lib/stdlib/src/ets.erl
index b5d3cd3c8d..4858c8d13c 100644
--- a/lib/stdlib/src/ets.erl
+++ b/lib/stdlib/src/ets.erl
@@ -1717,7 +1717,7 @@ get_line(P, Default) ->
 line_string(Binary) when is_binary(Binary) -> unicode:characters_to_list(Binary);
 line_string(Other) -> Other.
 
-nonl(S) -> string:strip(S, right, $\n).
+nonl(S) -> string:trim(S, trailing, "$\n").
 
 print_number(Tab, Key, Num) ->
     Os = ets:lookup(Tab, Key),
@@ -1746,7 +1746,7 @@ do_display_item(_Height, Width, I, Opos)  ->
     L = to_string(I),
     L2 = if
 	     length(L) > Width - 8 ->
-                 string:substr(L, 1, Width-13) ++ "  ...";
+                 string:slice(L, 0, Width-13) ++ "  ...";
 	     true ->
 		 L
 	 end,
diff --git a/lib/stdlib/src/filename.erl b/lib/stdlib/src/filename.erl
index 9bf4290916..63cfeae57b 100644
--- a/lib/stdlib/src/filename.erl
+++ b/lib/stdlib/src/filename.erl
@@ -1036,10 +1036,10 @@ basedir_linux(Type) ->
         user_log    -> getenv("XDG_CACHE_HOME", ?basedir_linux_user_log,   true);
         site_data   ->
             Base = getenv("XDG_DATA_DIRS",?basedir_linux_site_data,false),
-            string:tokens(Base,":");
+            string:lexemes(Base, ":");
         site_config ->
             Base = getenv("XDG_CONFIG_DIRS",?basedir_linux_site_config,false),
-            string:tokens(Base,":")
+            string:lexemes(Base, ":")
     end.
 
 -define(basedir_darwin_user_data,   "Library/Application Support").
diff --git a/lib/stdlib/src/io_lib_format.erl b/lib/stdlib/src/io_lib_format.erl
index 4b2d15c8b3..e345810ca0 100644
--- a/lib/stdlib/src/io_lib_format.erl
+++ b/lib/stdlib/src/io_lib_format.erl
@@ -380,7 +380,7 @@ float_e(_Fl, {Ds,E}, P) ->
 	{Fs,false} -> [Fs|float_exp(E-1)]
     end.
 
-%% float_man([Digit], Icount, Dcount) -> {[Chars],CarryFlag}.
+%% float_man([Digit], Icount, Dcount) -> {[Char],CarryFlag}.
 %%  Generate the characters in the mantissa from the digits with Icount
 %%  characters before the '.' and Dcount decimals. Handle carry and let
 %%  caller decide what to do at top.
@@ -395,7 +395,7 @@ float_man([D|Ds], I, Dc) ->
 	{Cs,false} -> {[D|Cs],false}
     end;
 float_man([], I, Dc) ->				%Pad with 0's
-    {string:chars($0, I, [$.|string:chars($0, Dc)]),false}.
+    {lists:duplicate(I, $0) ++ [$.|lists:duplicate(Dc, $0)],false}.
 
 float_man([D|_], 0) when D >= $5 -> {[],true};
 float_man([_|_], 0) -> {[],false};
@@ -405,7 +405,7 @@ float_man([D|Ds], Dc) ->
 	{Cs,true} -> {[D+1|Cs],false}; 
 	{Cs,false} -> {[D|Cs],false}
     end;
-float_man([], Dc) -> {string:chars($0, Dc),false}.	%Pad with 0's
+float_man([], Dc) -> {lists:duplicate(Dc, $0),false}.	%Pad with 0's
 
 %% float_exp(Exponent) -> [Char].
 %%  Generate the exponent of a floating point number. Always include sign.
@@ -429,7 +429,7 @@ fwrite_f(Fl, F, Adj, P, Pad) when P >= 1 ->
 float_f(Fl, Fd, P) when Fl < 0.0 ->
     [$-|float_f(-Fl, Fd, P)];
 float_f(Fl, {Ds,E}, P) when E =< 0 ->
-    float_f(Fl, {string:chars($0, -E+1, Ds),1}, P);	%Prepend enough 0's
+    float_f(Fl, {lists:duplicate(-E+1, $0)++Ds,1}, P);	%Prepend enough 0's
 float_f(_Fl, {Ds,E}, P) ->
     case float_man(Ds, E, P) of
 	{Fs,true} -> "1" ++ Fs;			%Handle carry
@@ -751,7 +751,7 @@ adjust(Data, Pad, right) -> [Pad|Data].
 flat_trunc(List, N) when is_integer(N), N >= 0 ->
     string:slice(List, 0, N).
 
-%% A deep version of string:chars/2,3
+%% A deep version of lists:duplicate/2
 
 chars(_C, 0) ->
     [];
diff --git a/lib/stdlib/src/lib.erl b/lib/stdlib/src/lib.erl
index c6eb0d7915..a7980cc294 100644
--- a/lib/stdlib/src/lib.erl
+++ b/lib/stdlib/src/lib.erl
@@ -646,7 +646,7 @@ pp_arguments(PF, As, I, Enc) ->
             Ll = length(L),
             A = list_to_atom(lists:duplicate(Ll, $a)),
             S0 = unicode:characters_to_list(PF([A | T], I+1), Enc),
-            brackets_to_parens([$[,L,string:sub_string(S0, 2+Ll)], Enc);
+            brackets_to_parens([$[,L,string:slice(S0, 1+Ll)], Enc);
         _ -> 
             brackets_to_parens(PF(As, I+1), Enc)
     end.
diff --git a/lib/stdlib/src/otp_internal.erl b/lib/stdlib/src/otp_internal.erl
index c59db903dc..7605ac763d 100644
--- a/lib/stdlib/src/otp_internal.erl
+++ b/lib/stdlib/src/otp_internal.erl
@@ -611,6 +611,52 @@ obsolete_1(filename, find_src, 2) ->
 obsolete_1(erlang, hash, 2) ->
     {removed, {erlang, phash2, 2}, "20.0"};
 
+%% Added in OTP-21
+obsolete_1(string, len, 1) ->
+    {deprecated, "deprecated; use string:length/3 instead"};
+obsolete_1(string, concat, 2) ->
+    {deprecated, "deprecated; use [Str1,Str2] instead"};
+obsolete_1(string, str, 2) ->
+    {deprecated, "deprecated; use string:find/2 instead"};
+obsolete_1(string, rstr, 2) ->
+    {deprecated, "deprecated; use string:find/3 instead"};
+obsolete_1(string, chr, 2) ->
+    {deprecated, "deprecated; use string:find/2 instead"};
+obsolete_1(string, rchr, 2) ->
+    {deprecated, "deprecated; use string:find/3 instead"};
+obsolete_1(string, span, 2) ->
+    {deprecated, "deprecated; use string:take/2 instead"};
+obsolete_1(string, cspan, 2) ->
+    {deprecated, "deprecated; use string:take/3 instead"};
+obsolete_1(string, substr, _) ->
+    {deprecated, "deprecated; use string:slice/3 instead"};
+obsolete_1(string, tokens, 2) ->
+    {deprecated, "deprecated; use string:lexemes/2 instead"};
+obsolete_1(string, chars, _) ->
+    {deprecated, "deprecated; use lists:duplicate/2 instead"};
+obsolete_1(string, copies, _) ->
+    {deprecated, "deprecated; use lists:duplicate/2 instead"};
+obsolete_1(string, words, _) ->
+    {deprecated, "deprecated; use string:lexemes/2 instead"};
+obsolete_1(string, strip, _) ->
+    {deprecated, "deprecated; use string:trim/3 instead"};
+obsolete_1(string, sub_word, _) ->
+    {deprecated, "deprecated; use string:nth_lexeme/3 instead"};
+obsolete_1(string, sub_string, _) ->
+    {deprecated, "deprecated; use string:slice/3 instead"};
+obsolete_1(string, left, _) ->
+    {deprecated, "deprecated; use string:pad/3 instead"};
+obsolete_1(string, right, _) ->
+    {deprecated, "deprecated; use string:pad/3 instead"};
+obsolete_1(string, centre, _) ->
+    {deprecated, "deprecated; use string:pad/3 instead"};
+obsolete_1(string, join, _) ->
+    {deprecated, "deprecated; use lists:join/2 instead"};
+obsolete_1(string, to_upper, _) ->
+    {deprecated, "deprecated; use string:uppercase/1 or string:titlecase/1 instead"};
+obsolete_1(string, to_lower, _) ->
+    {deprecated, "deprecated; use string:lowercase/1 or string:casefold/1 instead"};
+
 %% not obsolete
 
 obsolete_1(_, _, _) ->
diff --git a/lib/stdlib/src/slave.erl b/lib/stdlib/src/slave.erl
index d7cf6386f5..b3f3206d67 100644
--- a/lib/stdlib/src/slave.erl
+++ b/lib/stdlib/src/slave.erl
@@ -320,7 +320,7 @@ mk_cmd(Host, Name, Args, Waiter, Prog0) ->
 %% emulator and flags as the test node. The return from lib:progname()
 %% could then typically be '/<full_path_to>/cerl -gcov').
 quote_progname(Progname) ->
-    do_quote_progname(string:tokens(to_list(Progname)," ")).
+    do_quote_progname(string:lexemes(to_list(Progname)," ")).
 
 do_quote_progname([Prog]) ->
     "\""++Prog++"\"";
diff --git a/lib/stdlib/src/string.erl b/lib/stdlib/src/string.erl
index 4972da297d..5a4d2df2a6 100644
--- a/lib/stdlib/src/string.erl
+++ b/lib/stdlib/src/string.erl
@@ -87,6 +87,16 @@
 %%% May be removed
 -export([list_to_float/1, list_to_integer/1]).
 
+-deprecated([{len,1},{concat,2},
+             {str,2},{chr,2},{rchr,2},{rstr,2},
+             {span,2},{cspan,2},{substr,'_'},{tokens,2},
+             {chars,'_'},
+             {copies,2},{words,'_'},{strip,'_'},
+             {sub_word,'_'},{left,'_'},{right,'_'},
+             {sub_string,'_'},{centre,'_'},{join,2},
+             {to_upper,1}, {to_lower,1}
+            ]).
+
 %% Uses bifs: string:list_to_float/1 and string:list_to_integer/1
 -spec list_to_float(String) -> {Float, Rest} | {'error', Reason} when
       String :: string(),
diff --git a/lib/stdlib/uc_spec/gen_unicode_mod.escript b/lib/stdlib/uc_spec/gen_unicode_mod.escript
index 5b8763f576..674e5a0628 100755
--- a/lib/stdlib/uc_spec/gen_unicode_mod.escript
+++ b/lib/stdlib/uc_spec/gen_unicode_mod.escript
@@ -65,7 +65,7 @@ main(_) ->
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 
 parse_unicode_data(Line0, Acc) ->
-    Line = string:strip(Line0, right, $\n),
+    Line = string:chomp(Line0),
     [CodePoint,Name,_Cat,Class,_BiDi,Decomp,
      _N1,_N2,_N3,_BDMirror,_Uni1,_Iso|Case] = tokens(Line, ";"),
     {Dec,Comp} = case to_decomp(Decomp) of
@@ -78,14 +78,14 @@ parse_unicode_data(Line0, Acc) ->
      |Acc].
 
 to_class(String) ->
-    list_to_integer(string:strip(String, both)).
+    list_to_integer(string:trim(String, both)).
 
 to_decomp("") -> [];
 to_decomp("<" ++ Str) ->
-    [Tag,Rest]  = string:tokens(Str, ">"),
+    [Tag,Rest]  = string:lexemes(Str, ">"),
     {list_to_atom(Tag), to_decomp(Rest)};
 to_decomp(CodePoints) ->
-    CPL = string:tokens(CodePoints, " "),
+    CPL = string:lexemes(CodePoints, " "),
     [hex_to_int(CP) || CP <- CPL].
 
 to_case(["","",""]) -> [];
@@ -105,20 +105,20 @@ parse_special_casing(Line, Table) ->
     array:set(CP, Entry#cp{cs=Case}, Table).
 
 to_scase([Lower,Title,Upper|_]) ->
-    {unlist([hex_to_int(CP) || CP <- string:strip(string:tokens(Upper, " "), both)]),
-     unlist([hex_to_int(CP) || CP <- string:strip(string:tokens(Lower, " "), both)]),
-     unlist([hex_to_int(CP) || CP <- string:strip(string:tokens(Title, " "), both)]),
+    {unlist([hex_to_int(CP) || CP <- string:lexemes(Upper, " ")]),
+     unlist([hex_to_int(CP) || CP <- string:lexemes(Lower, " ")]),
+     unlist([hex_to_int(CP) || CP <- string:lexemes(Title, " ")]),
      []}.
 
 parse_case_folding(Line, Table) ->
     [CodePoint, Class0, CaseStr |_Comments] = tokens(Line, ";"),
-    Class = string:strip(Class0, both),
+    Class = string:trim(Class0, both),
     if Class =:= "T" -> Table; %% Do not support localization yet
        Class =:= "S" -> Table; %% Ignore simple
        true ->
             CP = hex_to_int(CodePoint),
             Case = unlist([hex_to_int(CPC) ||
-                              CPC <- string:strip(string:tokens(CaseStr, " "), both)]),
+                              CPC <- string:lexemes(CaseStr, " ")]),
             #cp{cs={U,L,T,_}} = Entry = array:get(CP, Table),
             array:set(CP, Entry#cp{cs={U,L,T,Case}}, Table)
     end.
@@ -869,10 +869,10 @@ optimize_ranges_1(Rs) ->
 
 hex_to_int([]) -> [];
 hex_to_int(HexStr) ->
-    list_to_integer(string:strip(HexStr, both), 16).
+    list_to_integer(string:trim(HexStr, both), 16).
 
 to_atom(Str) ->
-    list_to_atom(string:to_lower(string:strip(Str, both))).
+    list_to_atom(string:lowercase(string:trim(Str, both))).
 
 foldl(Fun, Acc, Fd) ->
     Get = fun() -> file:read_line(Fd) end,
@@ -892,7 +892,7 @@ foldl_1(Fun, Acc, Get) ->
 
 
 
-%% Differs from string:tokens, it returns empty string as token between two delimiters
+%% Differs from string:lexemes, it returns empty string as token between two delimiters
 tokens(S, [C]) ->
     tokens(lists:reverse(S), C, []).
 
diff --git a/lib/syntax_tools/src/erl_comment_scan.erl b/lib/syntax_tools/src/erl_comment_scan.erl
index 07e501e553..e3eb95b819 100644
--- a/lib/syntax_tools/src/erl_comment_scan.erl
+++ b/lib/syntax_tools/src/erl_comment_scan.erl
@@ -208,7 +208,7 @@ scan_comment([], Cs1, L, Col, M, Ack) ->
 seen_comment(Cs, Cs1, L, Col, M, Ack) ->
     %% Compute indentation and strip trailing spaces
     N = Col - M,
-    Text = lists:reverse(string:strip(Cs1, left)),
+    Text = lists:reverse(string:trim(Cs1, leading)),
     Ack1 = [{L, Col + 1, N, Text} | Ack],
     scan_lines(Cs, L + 1, 0, 0, Ack1).
 
diff --git a/lib/syntax_tools/src/merl_transform.erl b/lib/syntax_tools/src/merl_transform.erl
index b298bc407f..571d7e4d86 100644
--- a/lib/syntax_tools/src/merl_transform.erl
+++ b/lib/syntax_tools/src/merl_transform.erl
@@ -196,7 +196,7 @@ var_name(V) -> V.
 
 var_to_tag(V) when is_integer(V) -> V;
 var_to_tag(V) ->
-    list_to_atom(string:to_lower(atom_to_list(V))).
+    list_to_atom(string:lowercase(atom_to_list(V))).
 
 pre_expand_case(Expr, Clauses, Line) ->
     merl:qquote(Line, "merl:switch(_@expr, _@clauses)",
diff --git a/lib/tools/src/cover.erl b/lib/tools/src/cover.erl
index 5517882ffa..801bbc7461 100644
--- a/lib/tools/src/cover.erl
+++ b/lib/tools/src/cover.erl
@@ -2439,11 +2439,11 @@ do_analyse_to_file1(Module, OutFile, ErlFile, HTML) ->
                    Timestamp =
                        io_lib:format("~p-~s-~s at ~s:~s:~s",
                                      [Y,
-                                      string:right(integer_to_list(Mo), 2, $0),
-                                      string:right(integer_to_list(D),  2, $0),
-                                      string:right(integer_to_list(H),  2, $0),
-                                      string:right(integer_to_list(Mi), 2, $0),
-                                      string:right(integer_to_list(S),  2, $0)]),
+                                      string:pad(integer_to_list(Mo), 2, leading, $0),
+                                      string:pad(integer_to_list(D),  2, leading, $0),
+                                      string:pad(integer_to_list(H),  2, leading, $0),
+                                      string:pad(integer_to_list(Mi), 2, leading, $0),
+                                      string:pad(integer_to_list(S),  2, leading, $0)]),
 
                     H2Bin = unicode:characters_to_binary(
                               ["File generated from ",ErlFile," by COVER ",
@@ -2493,12 +2493,12 @@ print_lines(Module, CovLines, InFd, OutFd, L, HTML) ->
                     if N=:=0, HTML=:=true ->
                            LineNoNL = Line -- "\n",
                            Str = "     0",
-                           %%Str = string:right("0", 6, 32),
+                           %%Str = string:pad("0", 6, leading, $\s),
                            RedLine = ["<font color=red>",Str,fill1(),
                                       LineNoNL,"</font>\n"],
                            ok = file:write(OutFd, RedLine);
                        N < 1000000 ->
-                           Str = string:right(integer_to_list(N), 6, 32),
+                           Str = string:pad(integer_to_list(N), 6, leading, $\s),
                            ok = file:write(OutFd, [Str,fill1(),Line]);
                        N < 10000000 ->
                            Str = integer_to_list(N),
diff --git a/lib/tools/src/xref_utils.erl b/lib/tools/src/xref_utils.erl
index 02e207d40c..eca751337b 100644
--- a/lib/tools/src/xref_utils.erl
+++ b/lib/tools/src/xref_utils.erl
@@ -557,12 +557,9 @@ subdir(Dir, SubDir, true) ->
 
 %% Avoid "App-01.01" - the zeroes will be lost.
 filename2appl(File) ->
-    Pos = string:rstr(File, "-"),
-    true = Pos > 1,
-    V = string:sub_string(File, Pos+1),
-    true = string:len(V) > 0,
-    VsnT = string:tokens(V, "."),
-    ApplName = string:sub_string(File, 1, Pos-1),
+    [ApplName, V] = string:split(File, "-", trailing),
+    true = string:length(V) > 0,
+    VsnT = string:lexemes(V, "."),
     Vsn = [list_to_integer(Vsn) || Vsn <- VsnT],
     {list_to_atom(ApplName),Vsn}.