path: root/release-notes/OTP-21.0-rc2.README.txt

Patch Package:           OTP 21.0
Git Tag:                 OTP-21.0
Date:                    2018-05-29
Trouble Report Id:       OTP-10551, OTP-11462, OTP-11694, OTP-13019,
                         OTP-13073, OTP-13133, OTP-13295, OTP-13370,
                         OTP-13413, OTP-13713, OTP-13760, OTP-13761,
                         OTP-13764, OTP-14012, OTP-14015, OTP-14019,
                         OTP-14113, OTP-14256, OTP-14346, OTP-14359,
                         OTP-14370, OTP-14439, OTP-14459, OTP-14465,
                         OTP-14469, OTP-14492, OTP-14493, OTP-14496,
                         OTP-14497, OTP-14501, OTP-14502, OTP-14503,
                         OTP-14505, OTP-14508, OTP-14513, OTP-14518,
                         OTP-14525, OTP-14537, OTP-14543, OTP-14547,
                         OTP-14575, OTP-14577, OTP-14586, OTP-14589,
                         OTP-14594, OTP-14604, OTP-14610, OTP-14613,
                         OTP-14615, OTP-14624, OTP-14626, OTP-14637,
                         OTP-14651, OTP-14652, OTP-14654, OTP-14666,
                         OTP-14667, OTP-14675, OTP-14680, OTP-14681,
                         OTP-14682, OTP-14683, OTP-14687, OTP-14692,
                         OTP-14712, OTP-14713, OTP-14719, OTP-14726,
                         OTP-14729, OTP-14747, OTP-14764, OTP-14768,
                         OTP-14769, OTP-14774, OTP-14780, OTP-14782,
                         OTP-14785, OTP-14788, OTP-14789, OTP-14795,
                         OTP-14797, OTP-14808, OTP-14824, OTP-14826,
                         OTP-14830, OTP-14834, OTP-14844, OTP-14851,
                         OTP-14855, OTP-14861, OTP-14864, OTP-14880,
                         OTP-14882, OTP-14884, OTP-14888, OTP-14896,
                         OTP-14899, OTP-14900, OTP-14901, OTP-14902,
                         OTP-14903, OTP-14904, OTP-14909, OTP-14910,
                         OTP-14928, OTP-14931, OTP-14932, OTP-14934,
                         OTP-14937, OTP-14941, OTP-14943, OTP-14948,
                         OTP-14950, OTP-14951, OTP-14954, OTP-14955,
                         OTP-14956, OTP-14957, OTP-14958, OTP-14959,
                         OTP-14960, OTP-14961, OTP-14964, OTP-14965,
                         OTP-14966, OTP-14968, OTP-14969, OTP-14970,
                         OTP-14971, OTP-14974, OTP-14975, OTP-14976,
                         OTP-14977, OTP-14978, OTP-14979, OTP-14983,
                         OTP-14986, OTP-14988, OTP-14991, OTP-14992,
                         OTP-14993, OTP-14994, OTP-14996, OTP-14998,
                         OTP-15001, OTP-15002, OTP-15003, OTP-15006,
                         OTP-15008, OTP-15009, OTP-15013, OTP-15015,
                         OTP-15019, OTP-15021, OTP-15024, OTP-15025,
                         OTP-15026, OTP-15027, OTP-15028, OTP-15029,
                         OTP-15030, OTP-15031, OTP-15032, OTP-15033,
                         OTP-15035, OTP-15036, OTP-15037, OTP-15039,
                         OTP-15041, OTP-15042, OTP-15044, OTP-15045,
                         OTP-15047, OTP-15048, OTP-15049, OTP-15050,
                         OTP-15056, OTP-15062, OTP-15069, OTP-15071,
                         OTP-15072, OTP-15078, OTP-15079, OTP-15080,
                         OTP-15081, OTP-15082, OTP-15084, OTP-15085,
                         OTP-15086, OTP-15087, OTP-15088, OTP-15090,
                         OTP-15091, OTP-15093
Seq num:                 ERL-327, ERL-370, ERL-444, ERL-500, ERL-503,
                         ERL-511, ERL-514, ERL-549, ERL-550, ERL-557,
                         ERL-563, ERL-572, ERL-576, ERL-579, ERL-593,
                         ERL-598, ERL-601, ERL-613, ERL-614, ERL-615,
                         ERL-617, ERL-88
System:                  OTP
Release:                 21
Application:             asn1-5.0.6, common_test-1.16, compiler-7.2,
                         crypto-4.3, debugger-4.2.5, dialyzer-3.3,
                         diameter-2.1.5, edoc-0.9.3, eldap-1.2.4,
                         erl_docgen-0.8, erl_interface-3.10.3,
                         erts-10.0, et-1.6.2, eunit-2.3.6, ftp-1.0,
                         hipe-3.18, inets-7.0, jinterface-1.9,
                         kernel-6.0, mnesia-4.15.4, observer-2.8,
                         os_mon-2.4.5, parsetools-2.1.7,
                         public_key-1.6, reltool-0.7.6,
                         runtime_tools-1.13, sasl-3.2, ssh-4.7,
                         ssl-9.0, stdlib-3.5, syntax_tools-2.1.5,
                         tftp-1.0, tools-3.0, wx-1.8.4, xmerl-1.3.17
Predecessor:             OTP

 Check out the git tag OTP-21.0, and build a full OTP system including
 documentation.

 ---------------------------------------------------------------------
 --- HIGHLIGHTS ------------------------------------------------------
 ---------------------------------------------------------------------

  OTP-14370    Application(s): erts

               *** POTENTIAL INCOMPATIBILITY ***

               Truly asynchronous auto-connect. Earlier, when
               erlang:send was done toward an unconnected node, the
               function would not return until the connection setup
               had completed (or failed). Now the function returns
               directly after the signal has been enqueued and the
               connection setup started.

               The same applies to all distributed operations that may
               trigger auto-connect, i.e. '!', send, link, monitor,
               monitor_node, exit/2 and group_leader.

               The interface for all these functions are unchanged as
               they do not return connection failures. The only
               exception is erlang:monitor where a *possible
               incompatibility* is introduced: An attempt to monitor a
               process on a primitive node (such as erl_interface or
               jinterface), where remote process monitoring is not
               implemented, will no longer fail with badarg exception.
               Instead a monitor will be created, but it will only
               supervise the connection to the node.


  OTP-14459    Application(s): erts, kernel

               New functionality for implementation of alternative
               carriers for the Erlang distribution has been
               introduced. This mainly consists of support for usage
               of distribution controller processes (previously only
               ports could be used as distribution controllers). For
               more information see ERTS User's Guide ➜ How to
               implement an Alternative Carrier for the Erlang
               Distribution ➜ Distribution Module.


  OTP-14497    Application(s): compiler, erts

               *** POTENTIAL INCOMPATIBILITY ***

               Support for "tuple calls" have been removed from the
               run-time system. Tuple calls was an undocumented and
               unsupported feature which allowed the module argument
               for an apply operation to be a tuple: Var = dict:new(),
               Var:size(). This "feature" frequently caused confusion,
               especially when such call failed. The stacktrace would
               point out functions that don't exist in the source
               code.

               For legacy code that need to use parameterized modules
               or tuple calls for some other reason, there is a new
               compiler option called tuple_calls. When this option is
               given, the compiler will generate extra code that
               emulates the old behavior for calls where the module is
               a variable.


  OTP-14502    Application(s): erts

               Creation of small maps with literal keys has been
               optimized to be faster and potentially use less memory.
               The keys are combined into a literal key tuple which is
               put into the literal pool. The key tuple can be shared
               between many instances of maps having the same keys.


  OTP-14518    Application(s): erts, otp

               *** POTENTIAL INCOMPATIBILITY ***

               The non-smp emulators have been removed. This means
               that the configure options --disable-threads and
               --enable-plain-emulator have been removed and configure
               will now refuse to build Erlang/OTP on platforms
               without thread support.

               In order to achieve a similar setup as the non-smp
               emulator, it is possible to start Erlang/OTP with the
               +S 1 option.


  OTP-14626    Application(s): compiler, erts

               Loaded BEAM code in a 64-bit system requires less
               memory because of better packing of operands for
               instructions.

               These memory savings were achieved by major
               improvements to the beam_makeops scripts used when
               building the run time system and BEAM compiler. There
               is also new for documentation for beam_makeops that
               describes how new BEAM instructions and loader
               transformations can be implemented. The documentation
               is found in here in a source directory or git
               repository: erts/emulator/internal_doc/beam_makeops.md.
               An online version can be found here:
               https://github.com/erlang/otp/blob/master/erts/emulator/internal_doc/beam_makeops.md


  OTP-14692    Application(s): compiler, erts

               There is a new syntax in 'try/catch' for retrieving the
               stacktrace without calling 'erlang:get_stacktrace/0'.
               See the reference manual for a description of the new
               syntax. The 'erlang:get_stacktrace/0' BIF is now
               deprecated.


  OTP-14899    Application(s): erts, kernel

               seq_trace labels may now be any erlang term.


  OTP-14928    Application(s): erts

               *** POTENTIAL INCOMPATIBILITY ***

               The number of driver async threads will now default to
               1 as the standard drivers do not use them anymore.
               Users that changed this value to tweak the file driver
               should replace +A with +SDio since it now uses dirty IO
               schedulers instead of async threads.


  OTP-14968    Application(s): compiler
               Related Id(s): ERL-563

               When compiling modules with huge functions, the
               compiler would generate a lot of atoms for its
               internal, sometimes so many that the atom table would
               overflow. The compiler has been rewritten to generate
               far less internal atoms to avoid filling the atom
               table.


  OTP-15037    Application(s): compiler, erts
               Related Id(s): PR-1784, PR-1802

               Two new guards BIFs operating on maps have been added:
               map_get/2 and is_map_key/2. They do the same as
               maps:get/2 and maps:is_key/2, respectively, except that
               they are allowed to be used in guards.


  OTP-15087    Application(s): compiler
               Related Id(s): PR-1810

               Part of EEP-44 has been implemented.

               There is a new predefined macro called OTP_RELEASE
               which is an integer indicating the OTP release number
               (its value is 21 in this release).

               There are new preprocessor directives -if(Condition).
               and -elif(Condition).. The if/elif supports the builtin
               function defined(Symbol).


 ---------------------------------------------------------------------
 --- POTENTIAL INCOMPATIBILITIES -------------------------------------
 ---------------------------------------------------------------------

  OTP-11694    Application(s): erts

               The erlang:system_flag(scheduler_wall_time,Bool) call
               is now reference counted and will be turned off if the
               (last) process that started the performance statistics
               dies. Thus it is no longer possible to start the
               statistics with rpc:call(Node, erlang, system_flag,
               [scheduler_wall_time, true]) since it will be turned
               off directly afterwards when the rpc process dies.


  OTP-13073    Application(s): stdlib
               Related Id(s): PR-1595

               The semantics of timeout parameter
               {clean_timeout,infinity} to gen_statem:call/3 has been
               changed to use a proxy process for the call. With this
               change clean_timeout implicates a proxy process with no
               exceptions. This may be a hard to observe
               incompatibility: in the presence of network problems a
               late reply could arrive in the caller's message queue
               when catching errors. That will not happen after this
               correction.

               The semantics of timeout parameter infinity has not
               been changed.


  OTP-13295    Application(s): erts, kernel, sasl, stdlib

               A new logging API is added to Erlang/OTP, see the
               logger(3) manual page, and section Logging in the
               Kernel User's Guide.

               Calls to error_logger are automatically redirected to
               the new API, and legacy error logger event handlers can
               still be used. It is, however, recommended to use the
               Logger API directly when writing new code.

               Notice the following potential incompatibilities:

               -- Kernel configuration parameters error_logger still
               works, but is overruled if the default handler's output
               destination is configured with Kernel configuration
               parameter logger.

               In general, parameters for configuring error logger are
               overwritten by new parameters for configuring Logger.

               -- The concept of SASL error logging is deprecated,
               meaning that by default the SASL application does not
               affect which log events are logged.

               By default, supervisor reports and crash reports are
               logged by the default Logger handler started by Kernel,
               and end up at the same destination (terminal or file)
               as other standard log event from Erlang/OTP.

               Progress reports are not logged by default, but can be
               enabled with the Kernel configuration parameter
               logger_progress_reports.

               To obtain backwards compatibility with the SASL error
               logging functionality from earlier releases, set Kernel
               configuration parameter logger_sasl_compatible to true.
               This prevents the default Logger handler from logging
               any supervisor-, crash-, or progress reports. Instead,
               SASL adds a separate Logger handler during application
               start, which takes care of these log events. The SASL
               configuration parameters sasl_error_logger and
               sasl_errlog_type specify the destination (terminal or
               file) and severity level to log for these events.


  OTP-13761    Application(s): kernel
               Related Id(s): ERL-503

               No resolver backend returns V4Mapped IPv6 addresses any
               more. This was inconsistent before, some did, some did
               not. To facilitate working with such addresses a new
               function inet:ipv4_mapped_ipv6_address/1 has been
               added.


  OTP-14256    Application(s): erts

               The file driver has been rewritten as a NIF, decreasing
               the latency of file operations. Two notable
               incompatibilities are:

               -- The use_threads option for file:sendfile/5 no longer
               has any effect; we either use non-blocking sendfile(2)
               or fall back to file:read + gen_tcp:send.

               -- The file-specific DTrace probes have been removed.
               The same effect can be achieved with normal tracing
               together with the nif__entry/nif__return probes to
               track scheduling.


  OTP-14370    Application(s): erts

               *** HIGHLIGHT ***

               Truly asynchronous auto-connect. Earlier, when
               erlang:send was done toward an unconnected node, the
               function would not return until the connection setup
               had completed (or failed). Now the function returns
               directly after the signal has been enqueued and the
               connection setup started.

               The same applies to all distributed operations that may
               trigger auto-connect, i.e. '!', send, link, monitor,
               monitor_node, exit/2 and group_leader.

               The interface for all these functions are unchanged as
               they do not return connection failures. The only
               exception is erlang:monitor where a *possible
               incompatibility* is introduced: An attempt to monitor a
               process on a primitive node (such as erl_interface or
               jinterface), where remote process monitoring is not
               implemented, will no longer fail with badarg exception.
               Instead a monitor will be created, but it will only
               supervise the connection to the node.


  OTP-14439    Application(s): compiler, dialyzer, erts, stdlib

               Changed the default behaviour of .erlang loading:
               .erlang is no longer loaded from the current directory.
               c:erlangrc(PathList) can be used to search and load an
               .erlang file from user specified directories.

               escript, erlc, dialyzer and typer no longer load an
               .erlang at all.


  OTP-14469    Application(s): sasl

               The old and outdated "Status Inspection" tool (modules
               si and si_sasl_sup) is removed.


  OTP-14497    Application(s): compiler, erts

               *** HIGHLIGHT ***

               Support for "tuple calls" have been removed from the
               run-time system. Tuple calls was an undocumented and
               unsupported feature which allowed the module argument
               for an apply operation to be a tuple: Var = dict:new(),
               Var:size(). This "feature" frequently caused confusion,
               especially when such call failed. The stacktrace would
               point out functions that don't exist in the source
               code.

               For legacy code that need to use parameterized modules
               or tuple calls for some other reason, there is a new
               compiler option called tuple_calls. When this option is
               given, the compiler will generate extra code that
               emulates the old behavior for calls where the module is
               a variable.


  OTP-14508    Application(s): erts

               When an exception is thrown, include the arguments of
               the call in the stacktrace for BIFs band, bor, bsl,
               bsr, bxor, div, rem and the operators +, -, * and /.


  OTP-14518    Application(s): erts, otp

               *** HIGHLIGHT ***

               The non-smp emulators have been removed. This means
               that the configure options --disable-threads and
               --enable-plain-emulator have been removed and configure
               will now refuse to build Erlang/OTP on platforms
               without thread support.

               In order to achieve a similar setup as the non-smp
               emulator, it is possible to start Erlang/OTP with the
               +S 1 option.


  OTP-14543    Application(s): erts, kernel, stdlib
               Related Id(s): ERL-370

               File operations used to accept filenames containing
               null characters (integer value zero). This caused the
               name to be truncated and in some cases arguments to
               primitive operations to be mixed up. Filenames
               containing null characters inside the filename are now
               *rejected* and will cause primitive file operations to
               fail.

               Also environment variable operations used to accept
               names and values of environment variables containing
               null characters (integer value zero). This caused
               operations to silently produce erroneous results.
               Environment variable names and values containing null
               characters inside the name or value are now *rejected*
               and will cause environment variable operations to fail.

               Primitive environment variable operations also used to
               accept the $= character in environment variable names
               causing various problems. $= characters in environment
               variable names are now also *rejected*.

               Also os:cmd/1 now reject null characters inside its
               command.

               erlang:open_port/2 will also reject null characters
               inside the port name from now on.


  OTP-14577    Application(s): stdlib

               filelib:wildcard() now allows characters with a special
               meaning to be escaped using backslashes.

               This is an incompatible change, but note that the use
               of backslashes in wildcards would already work
               differently on Windows and Unix. Existing calls to
               filelib:wildcard() needs to be updated. On Windows,
               directory separators must always be written as a slash.


  OTP-14666    Application(s): erts, kernel

               os:putenv and os:getenv no longer access the process
               environment directly and instead work on a thread-safe
               emulation. The only observable difference is that it's
               *not* kept in sync with libc getenv(3) / putenv(3), so
               those who relied on that behavior in drivers or NIFs
               will need to add manual synchronization.

               On Windows this means that you can no longer resolve
               DLL dependencies by modifying the PATH just before
               loading the driver/NIF. To make this less of a problem,
               the emulator now adds the target DLL's folder to the
               DLL search path.


  OTP-14768    Application(s): ssl

               For security reasons no longer support 3-DES cipher
               suites by default


  OTP-14769    Application(s): ssl

               For security reasons RSA-key exchange cipher suites are
               no longer supported by default


  OTP-14789    Application(s): ssl

               The interoperability option to fallback to insecure
               renegotiation now has to be explicitly turned on.


  OTP-14824    Application(s): ssl

               Drop support for SSLv2 enabled clients. SSLv2 has been
               broken for decades and never supported by the Erlang
               SSL/TLS implementation. This option was by default
               disabled and enabling it has proved to sometimes break
               connections not using SSLv2 enabled clients.


  OTP-14851    Application(s): ssh

               An option exec for daemons implementing the 'exec' has
               existed a long time but has been undocumented. The old
               behaviour is kept for compatibility EXCEPT that error
               messages are changed and are sent as "stderror" text.

               A new option value is defined to make it much more easy
               to implement an own exec server.


  OTP-14882    Application(s): ssl

               Remove CHACHA20_POLY1305 ciphers form default for now.
               We have discovered interoperability problems, ERL-538,
               that we believe needs to be solved in crypto.


  OTP-14928    Application(s): erts

               *** HIGHLIGHT ***

               The number of driver async threads will now default to
               1 as the standard drivers do not use them anymore.
               Users that changed this value to tweak the file driver
               should replace +A with +SDio since it now uses dirty IO
               schedulers instead of async threads.


  OTP-14961    Application(s): erts, tools

               Added instrument:allocations and instrument:carriers
               for retrieving information about memory utilization and
               fragmentation.

               The old instrument interface has been removed, as have
               the related options +Mim and +Mis.


  OTP-14964    Application(s): erts
               Related Id(s): OTP-14589

               The process suspend functionality used by the
               erlang:suspend_process/2 BIF has been reimplemented
               using the newly introduced true asynchronous signaling
               between processes. This mainly to reduce memory usage
               in the process control block of all processes, but also
               in order to simplify the implementation.

               WARNING: You can easily create deadlocks if processes
               suspends each other (directly or in circles). In ERTS
               versions prior to ERTS version 10.0, the runtime system
               prevented such deadlocks, but this prevention has now
               been removed due to performance reasons.

               Other ERTS internal functionality that used the
               previous process suspend functionality have also been
               reimplemented to use asynchronous signaling instead.


  OTP-14986    Application(s): erts
               Related Id(s): PR-1745

               erlang:process_info/1 has been changed to no longer
               include messages by default. Instead
               erlang:process_info/2 should be used.


  OTP-15002    Application(s): ssh
               Related Id(s): OTP-15030

               The type specifications in SSH are reworked and the
               following types are renamed:

               ssh:ssh_connection_ref() is changed to
               ssh:connection_ref(),

               ssh:ssh_daemon_ref() is changed to ssh:daemon_ref(),

               ssh:ssh_channel_id() is changed to ssh:channel_id().


  OTP-15071    Application(s): kernel

               The included_applications key are no longer duplicated
               as application environment variable. Earlier, the
               included applications could be read both with
               application:get[_all]_env(...) and
               application:get[_all]_key(...) functions. Now, it can
               only be read with application:get[_all]_key(...).


  OTP-15072    Application(s): stdlib
               Related Id(s): 1786, PR

               The lib module is removed:

               -- lib:error_message/2 is removed.

               -- lib:flush_receive/0 is removed.

               -- lib:nonl/1 is removed.

               -- lib:progname/0 is replaced by ct:get_progname/0.

               -- lib:send/2 is removed.

               -- lib:sendw/2 is removed.


 ---------------------------------------------------------------------
 --- asn1-5.0.6 ------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-15036    Application(s): asn1, edoc, eldap, syntax_tools

               Update to use the new string api instead of the old.


 Full runtime dependencies of asn1-5.0.6: erts-7.0, kernel-3.0,
 stdlib-2.0


 ---------------------------------------------------------------------
 --- common_test-1.16 ------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14902    Application(s): common_test, observer, public_key, ssl

               Use uri_string module instead of http_uri.


 Full runtime dependencies of common_test-1.16: compiler-6.0,
 crypto-3.6, debugger-4.1, erts-7.0, ftp-1.0.0, inets-6.0, kernel-4.0,
 observer-2.1, runtime_tools-1.8.16, sasl-2.4.2, snmp-5.1.2, ssh-4.0,
 stdlib-3.5, syntax_tools-1.7, tools-2.8, xmerl-1.3.8


 ---------------------------------------------------------------------
 --- compiler-7.2 ----------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14855    Application(s): compiler
               Related Id(s): ERL-549

               Fixed an error in an optimization pass that caused
               impossible tuple matching.


  OTP-14992    Application(s): compiler
               Related Id(s): ERL-572

               The exception thrown when a list comprehension was
               given a non-list term was not always correct.


 --- Improvements and New Features ---

  OTP-14439    Application(s): compiler, dialyzer, erts, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               Changed the default behaviour of .erlang loading:
               .erlang is no longer loaded from the current directory.
               c:erlangrc(PathList) can be used to search and load an
               .erlang file from user specified directories.

               escript, erlc, dialyzer and typer no longer load an
               .erlang at all.


  OTP-14497    Application(s): compiler, erts

               *** HIGHLIGHT ***

               *** POTENTIAL INCOMPATIBILITY ***

               Support for "tuple calls" have been removed from the
               run-time system. Tuple calls was an undocumented and
               unsupported feature which allowed the module argument
               for an apply operation to be a tuple: Var = dict:new(),
               Var:size(). This "feature" frequently caused confusion,
               especially when such call failed. The stacktrace would
               point out functions that don't exist in the source
               code.

               For legacy code that need to use parameterized modules
               or tuple calls for some other reason, there is a new
               compiler option called tuple_calls. When this option is
               given, the compiler will generate extra code that
               emulates the old behavior for calls where the module is
               a variable.


  OTP-14505    Application(s): compiler

               In code such as example({ok, Val}) -> {ok, Val}. a
               tuple would be built. The compiler will now
               automatically rewrite the code to
               example({ok,Val}=Tuple) -> Tuple. which will reduce
               code size, execution time, and remove GC pressure.


  OTP-14525    Application(s): compiler

               The optimization of case expression where only one of
               the case arms can execute successfully has been
               improved.


  OTP-14594    Application(s): compiler
               Related Id(s): ERL-444

               Some uses of binary matching has been slightly
               improved, eliminating unnecessary register shuffling.


  OTP-14615    Application(s): compiler
               Related Id(s): PR-1558

               There is a new {compile_info,Info} option for the
               compiler that allows BEAM-based languages such as
               Elixir and LFE to add their own compiler versions.


  OTP-14626    Application(s): compiler, erts

               *** HIGHLIGHT ***

               Loaded BEAM code in a 64-bit system requires less
               memory because of better packing of operands for
               instructions.

               These memory savings were achieved by major
               improvements to the beam_makeops scripts used when
               building the run time system and BEAM compiler. There
               is also new for documentation for beam_makeops that
               describes how new BEAM instructions and loader
               transformations can be implemented. The documentation
               is found in here in a source directory or git
               repository: erts/emulator/internal_doc/beam_makeops.md.
               An online version can be found here:
               https://github.com/erlang/otp/blob/master/erts/emulator/internal_doc/beam_makeops.md


  OTP-14654    Application(s): compiler

               Size calculations for binary constructions has been
               somewhat optimized, producing smaller code.


  OTP-14683    Application(s): compiler, erts

               When the value returned from a 'catch' expression is
               ignored, no stacktrace will be built if an exception is
               caught. That will save time and produce less garbage.
               There are also some minor optimizations of 'try/catch'
               both in the compiler and run-time system.


  OTP-14692    Application(s): compiler, erts

               *** HIGHLIGHT ***

               There is a new syntax in 'try/catch' for retrieving the
               stacktrace without calling 'erlang:get_stacktrace/0'.
               See the reference manual for a description of the new
               syntax. The 'erlang:get_stacktrace/0' BIF is now
               deprecated.


  OTP-14712    Application(s): compiler

               The following is an internal change in the compiler,
               that is not noticeable for normal use of the compiler:
               The module v3_life has been removed. Its functionality
               has been simplified and integrated into v3_codegen.


  OTP-14774    Application(s): compiler

               The optimization of binary matching that delays
               creation of sub binaries (see the Efficiency Guide)
               could be thwarted by the argument order and could be
               necessary to change the argument order. The compiler
               has now become smarter and can handle any argument
               order.


  OTP-14808    Application(s): compiler
               Related Id(s): ERL-514

               When the compiler was faced with complex case
               expressions it would unnecessarily allocate stack
               elements and shuffle data between x and y registers.
               Improved code generation to only allocate a stack frame
               when strictly necessary.


  OTP-14830    Application(s): compiler, erts

               There is a new option 'makedep_side_effect' for the
               compiler and -MMD for 'erlc' that generates
               dependencies and continues to compile as normal.


  OTP-14968    Application(s): compiler
               Related Id(s): ERL-563

               *** HIGHLIGHT ***

               When compiling modules with huge functions, the
               compiler would generate a lot of atoms for its
               internal, sometimes so many that the atom table would
               overflow. The compiler has been rewritten to generate
               far less internal atoms to avoid filling the atom
               table.


  OTP-15003    Application(s): compiler, stdlib

               External funs with literal values for module, name, and
               arity (e.g. erlang:abs/1) are now treated as literals.
               That means more efficient code that produces less
               garbage on the heap.


  OTP-15037    Application(s): compiler, erts
               Related Id(s): PR-1784, PR-1802

               *** HIGHLIGHT ***

               Two new guards BIFs operating on maps have been added:
               map_get/2 and is_map_key/2. They do the same as
               maps:get/2 and maps:is_key/2, respectively, except that
               they are allowed to be used in guards.


  OTP-15044    Application(s): compiler
               Related Id(s): ERL-614

               A call or apply of a literal external fun will be
               replaced with a direct call.


  OTP-15087    Application(s): compiler
               Related Id(s): PR-1810

               *** HIGHLIGHT ***

               Part of EEP-44 has been implemented.

               There is a new predefined macro called OTP_RELEASE
               which is an integer indicating the OTP release number
               (its value is 21 in this release).

               There are new preprocessor directives -if(Condition).
               and -elif(Condition).. The if/elif supports the builtin
               function defined(Symbol).


 Full runtime dependencies of compiler-7.2: crypto-3.6, erts-9.0,
 hipe-3.12, kernel-4.0, stdlib-2.5


 ---------------------------------------------------------------------
 --- crypto-4.3 ------------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14956    Application(s): crypto
               Related Id(s): ERL-579

               Removed two undocumented and erroneous functions
               (crypto:dh_generate_parameters/2 and
               crypto:dh_check/1).


  OTP-15088    Application(s): crypto

               Fixed bug causing VM crash if doing runtime upgrade of
               a crypto module built against OpenSSL older than
               0.9.8h. Bug exists since OTP-20.2.


 --- Improvements and New Features ---

  OTP-13370    Application(s): crypto
               Related Id(s): PR-1573

               A new rand plugin algorithm has been implemented in
               crypto, that is: crypto_cache. It uses strong random
               bytes as randomness source and caches them to get good
               speed. See crypto:rand_seed_alg/1.


  OTP-14864    Application(s): crypto

               Diffie-Hellman key functions are re-written with the
               EVP_PKEY api.


 Full runtime dependencies of crypto-4.3: erts-9.0, kernel-5.3,
 stdlib-3.4


 ---------------------------------------------------------------------
 --- debugger-4.2.5 --------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14957    Application(s): debugger
               Related Id(s): PR-1741

               Fix a bug where calling a fun inside a binary would
               crash the Debugger.


 Full runtime dependencies of debugger-4.2.5: compiler-5.0, erts-9.0,
 kernel-5.3, stdlib-3.4, wx-1.2


 ---------------------------------------------------------------------
 --- dialyzer-3.3 ----------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14439    Application(s): compiler, dialyzer, erts, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               Changed the default behaviour of .erlang loading:
               .erlang is no longer loaded from the current directory.
               c:erlangrc(PathList) can be used to search and load an
               .erlang file from user specified directories.

               escript, erlc, dialyzer and typer no longer load an
               .erlang at all.


  OTP-14493    Application(s): dialyzer
               Related Id(s): PR-1434

               Dialyzer can no longer read BEAM files created with OTP
               19 or earlier.


  OTP-14937    Application(s): dialyzer
               Related Id(s): PR-1719

               Speed up the computation of MD5 sums.


  OTP-14970    Application(s): dialyzer
               Related Id(s): PR-1722

               Fix a situation where Dialyzer unnecessarily discarded
               contract information, resulting in missed warnings.


  OTP-15079    Application(s): dialyzer
               Related Id(s): ERL-593

               Do not emit warnings for fun expressions residing in
               code that cannot be run. This is consistent with how
               Dialyzer treats other code that cannot be run.


 Full runtime dependencies of dialyzer-3.3: compiler-7.0, erts-9.0,
 hipe-3.16.1, kernel-5.3, stdlib-3.4, syntax_tools-2.0, wx-1.2


 ---------------------------------------------------------------------
 --- diameter-2.1.5 --------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-15045    Application(s): diameter

               Fix documentation typos.


 Full runtime dependencies of diameter-2.1.5: erts-6.4, kernel-3.2,
 ssl-6.0, stdlib-2.4


 ---------------------------------------------------------------------
 --- edoc-0.9.3 ------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-15036    Application(s): asn1, edoc, eldap, syntax_tools

               Update to use the new string api instead of the old.


 Full runtime dependencies of edoc-0.9.3: erts-6.0, inets-5.10,
 kernel-3.0, stdlib-2.5, syntax_tools-1.6.14, xmerl-1.3.7


 ---------------------------------------------------------------------
 --- eldap-1.2.4 -----------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-15036    Application(s): asn1, edoc, eldap, syntax_tools

               Update to use the new string api instead of the old.


 Full runtime dependencies of eldap-1.2.4: asn1-3.0, erts-6.0,
 kernel-3.0, ssl-5.3.4, stdlib-2.0


 ---------------------------------------------------------------------
 --- erl_docgen-0.8 --------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-15091    Application(s): erl_docgen

               Update makefile so db_funcs.xsl is a part of the
               installed application.


 --- Improvements and New Features ---

  OTP-14979    Application(s): erl_docgen, otp

               Add a hoverable element to the titles in the html
               documentation with a link to github where the
               documentation can be edited.

               Make the anchors in the html User's Guide and system
               documentation use the title of the sections instead of
               a generated id.


 Full runtime dependencies of erl_docgen-0.8: edoc-0.7.13, erts-9.0,
 stdlib-3.4, xmerl-1.3.7


 ---------------------------------------------------------------------
 --- erl_interface-3.10.3 --------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-15033    Application(s): erl_interface

               Fix bug where calling erl_init on certain platforms
               could result in a buffer overflow bug.


 ---------------------------------------------------------------------
 --- erts-10.0 -------------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14019    Application(s): erts, kernel, stdlib
               Related Id(s): ERL-550

               The type specifications for file:posix/0 and
               inet:posix/0 have been updated according to which
               errors file and socket operations should be able to
               return.


  OTP-14537    Application(s): erts
               Related Id(s): PR1529

               Fix error printout from run_erl and a bug that could
               cause unintended fds to be leaked into the started
               program.


  OTP-14543    Application(s): erts, kernel, stdlib
               Related Id(s): ERL-370

               *** POTENTIAL INCOMPATIBILITY ***

               File operations used to accept filenames containing
               null characters (integer value zero). This caused the
               name to be truncated and in some cases arguments to
               primitive operations to be mixed up. Filenames
               containing null characters inside the filename are now
               *rejected* and will cause primitive file operations to
               fail.

               Also environment variable operations used to accept
               names and values of environment variables containing
               null characters (integer value zero). This caused
               operations to silently produce erroneous results.
               Environment variable names and values containing null
               characters inside the name or value are now *rejected*
               and will cause environment variable operations to fail.

               Primitive environment variable operations also used to
               accept the $= character in environment variable names
               causing various problems. $= characters in environment
               variable names are now also *rejected*.

               Also os:cmd/1 now reject null characters inside its
               command.

               erlang:open_port/2 will also reject null characters
               inside the port name from now on.


  OTP-14652    Application(s): erts

               Fix bugs related to the bookkeeping of microstate
               accounting states.


  OTP-14666    Application(s): erts, kernel

               *** POTENTIAL INCOMPATIBILITY ***

               os:putenv and os:getenv no longer access the process
               environment directly and instead work on a thread-safe
               emulation. The only observable difference is that it's
               *not* kept in sync with libc getenv(3) / putenv(3), so
               those who relied on that behavior in drivers or NIFs
               will need to add manual synchronization.

               On Windows this means that you can no longer resolve
               DLL dependencies by modifying the PATH just before
               loading the driver/NIF. To make this less of a problem,
               the emulator now adds the target DLL's folder to the
               DLL search path.


  OTP-14713    Application(s): erts
               Related Id(s): ERL-500

               Corrected erlang:is_builtin(erlang, M, F) to return
               true for apply/2 and yield/0.


  OTP-14719    Application(s): erts

               Fixed a bug where the PATH environment variable wasn't
               updated correctly on a release downgrade, effectively
               keeping the PATH of the new release.


  OTP-14782    Application(s): erts
               Related Id(s): ERL-511

               A receive optimization that avoids scanning the entire
               message queue when receiving a message containing a
               freshly created reference could in rare circumstances
               (involving recursive calls to the functions that does
               the receive) cause the receive to hang. This has been
               corrected.


  OTP-14909    Application(s): erts
               Related Id(s): PR-1692

               Fix building of Erlang/OTP on platforms which have
               small data area with short addressing. For example the
               PowerPC/RTEMS platform.


  OTP-14931    Application(s): erts

               Fixed a crash when enif_make_binary is called with a
               binary produced by enif_inspect_binary in a different
               environment.


  OTP-14932    Application(s): erts

               Fixed a crash when enif_make_binary is called more than
               once with a binary that had previously been added to an
               enif_ioq.


  OTP-14943    Application(s): erts
               Related Id(s): ERL-576

               The erl_child_setup program now ignores SIGTERM
               signals.


  OTP-14977    Application(s): erts

               Force 64-bit alignment on pre-allocators on
               architectures which needs it.


  OTP-14978    Application(s): erts

               Fixed a bug where dirty scheduler picked up non-dirty
               work.


  OTP-15001    Application(s): erts, kernel

               Calls to gen_tcp:send/2 on closed sockets now returns
               {error, closed} instead of {error,enotconn}.


  OTP-15008    Application(s): erts

               erlang:monotonic_time/1 failed with badarg when passing
               the perf_counter time unit as argument.


  OTP-15013    Application(s): erts

               Fix bug where rapid init:restart() calls would
               sometimes crash because a code load request leaked in
               between the restarts.


  OTP-15015    Application(s): erts
               Related Id(s): OTP-14890

               Improve float_to_list(F, [{decimals,D}]) to closer
               conform with io_lib:format("~.*f", [D,F]).

               There are however, still cases when float_to_list does
               not produce the exact same result as io_lib:format,
               especially for large values F and/or many decimals D.


  OTP-15024    Application(s): erts

               Fixed a deadlock that would occur on certain allocators
               when a reallocation failed with +ramv enabled.


  OTP-15029    Application(s): erts

               Fix bug that made it impossible to use an erl_tracer as
               the seq_trace trace receiver.


  OTP-15032    Application(s): erts

               Fix bug where a large (> 1 GB) emulator generated error
               logger message would cause the emulator to crash.


  OTP-15062    Application(s): erts
               Related Id(s): ERL-615

               The emulator will no longer crash when reading the file
               information of an ordinary file that has an NTFS
               reparse point, such as files stored in a
               OneDrive-mapped folder.


  OTP-15080    Application(s): erts

               Fixed bug in enif_binary_to_term which could cause
               memory corruption for immediate terms (atoms, small
               integers, pids, ports, empty lists).


  OTP-15085    Application(s): erts

               Fixed bug in erlang:system_profile/2 that could cause
               superfluous {profile,_,active,_,_} messages for
               terminating processes.


  OTP-15090    Application(s): erts

               On OSs with per thread CPU time support, change
               cpu_timestamp in erlang:trace/3 to use it instead of
               per process CPU time. This makes this option useable on
               such OSs when running multiple schedulers.


 --- Improvements and New Features ---

  OTP-11462    Application(s): erts

               It is now possible to open device files and FIFOs with
               file:open/2.


  OTP-11694    Application(s): erts

               *** POTENTIAL INCOMPATIBILITY ***

               The erlang:system_flag(scheduler_wall_time,Bool) call
               is now reference counted and will be turned off if the
               (last) process that started the performance statistics
               dies. Thus it is no longer possible to start the
               statistics with rpc:call(Node, erlang, system_flag,
               [scheduler_wall_time, true]) since it will be turned
               off directly afterwards when the rpc process dies.


  OTP-13295    Application(s): erts, kernel, sasl, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               A new logging API is added to Erlang/OTP, see the
               logger(3) manual page, and section Logging in the
               Kernel User's Guide.

               Calls to error_logger are automatically redirected to
               the new API, and legacy error logger event handlers can
               still be used. It is, however, recommended to use the
               Logger API directly when writing new code.

               Notice the following potential incompatibilities:

               -- Kernel configuration parameters error_logger still
               works, but is overruled if the default handler's output
               destination is configured with Kernel configuration
               parameter logger.

               In general, parameters for configuring error logger are
               overwritten by new parameters for configuring Logger.

               -- The concept of SASL error logging is deprecated,
               meaning that by default the SASL application does not
               affect which log events are logged.

               By default, supervisor reports and crash reports are
               logged by the default Logger handler started by Kernel,
               and end up at the same destination (terminal or file)
               as other standard log event from Erlang/OTP.

               Progress reports are not logged by default, but can be
               enabled with the Kernel configuration parameter
               logger_progress_reports.

               To obtain backwards compatibility with the SASL error
               logging functionality from earlier releases, set Kernel
               configuration parameter logger_sasl_compatible to true.
               This prevents the default Logger handler from logging
               any supervisor-, crash-, or progress reports. Instead,
               SASL adds a separate Logger handler during application
               start, which takes care of these log events. The SASL
               configuration parameters sasl_error_logger and
               sasl_errlog_type specify the destination (terminal or
               file) and severity level to log for these events.


  OTP-13760    Application(s): erts
               Related Id(s): PR-1592

               gen_sctp:connect_init/4 or rather connect in inet_drv.c
               for SCTP has been fixed to not check the write file
               descriptor for writeability after a connect, since for
               SCTP (SOCK_SEQPACKET) that property does not seem to be
               any kind of indicator for when a connect has finished.
               This fixes connects that the OS returned as "in
               progress" that was misinterpreted by
               gen_sctp:connect_init as failed.


  OTP-14256    Application(s): erts

               *** POTENTIAL INCOMPATIBILITY ***

               The file driver has been rewritten as a NIF, decreasing
               the latency of file operations. Two notable
               incompatibilities are:

               -- The use_threads option for file:sendfile/5 no longer
               has any effect; we either use non-blocking sendfile(2)
               or fall back to file:read + gen_tcp:send.

               -- The file-specific DTrace probes have been removed.
               The same effect can be achieved with normal tracing
               together with the nif__entry/nif__return probes to
               track scheduling.


  OTP-14346    Application(s): erts

               The I/O polling functionality of erts has been
               re-written to better make use of the OSs polling
               mechanisms. This change means that erts will now always
               prefer to use a kernel-polling mechanism if possible.
               Also all of the I/O polling has been moved to dedicated
               threads instead of being placed in the scheduler loops.

               As a result of this, the erl options +K and +secio have
               been removed. It is still possible to disable
               kernel-poll, but it has to be done at compile time
               through the configure option --disable-kernel-poll.

               The new erl options +IOt and +IOp can be used to change
               how many IO poll threads and poll sets that erts should
               use. See their respective documentation for more
               details.


  OTP-14370    Application(s): erts

               *** HIGHLIGHT ***

               *** POTENTIAL INCOMPATIBILITY ***

               Truly asynchronous auto-connect. Earlier, when
               erlang:send was done toward an unconnected node, the
               function would not return until the connection setup
               had completed (or failed). Now the function returns
               directly after the signal has been enqueued and the
               connection setup started.

               The same applies to all distributed operations that may
               trigger auto-connect, i.e. '!', send, link, monitor,
               monitor_node, exit/2 and group_leader.

               The interface for all these functions are unchanged as
               they do not return connection failures. The only
               exception is erlang:monitor where a *possible
               incompatibility* is introduced: An attempt to monitor a
               process on a primitive node (such as erl_interface or
               jinterface), where remote process monitoring is not
               implemented, will no longer fail with badarg exception.
               Instead a monitor will be created, but it will only
               supervise the connection to the node.


  OTP-14439    Application(s): compiler, dialyzer, erts, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               Changed the default behaviour of .erlang loading:
               .erlang is no longer loaded from the current directory.
               c:erlangrc(PathList) can be used to search and load an
               .erlang file from user specified directories.

               escript, erlc, dialyzer and typer no longer load an
               .erlang at all.


  OTP-14459    Application(s): erts, kernel

               *** HIGHLIGHT ***

               New functionality for implementation of alternative
               carriers for the Erlang distribution has been
               introduced. This mainly consists of support for usage
               of distribution controller processes (previously only
               ports could be used as distribution controllers). For
               more information see ERTS User's Guide ➜ How to
               implement an Alternative Carrier for the Erlang
               Distribution ➜ Distribution Module.


  OTP-14492    Application(s): erts

               Add support for the lcc compiler and in extension the
               Elbrus 2000 platform.


  OTP-14497    Application(s): compiler, erts

               *** HIGHLIGHT ***

               *** POTENTIAL INCOMPATIBILITY ***

               Support for "tuple calls" have been removed from the
               run-time system. Tuple calls was an undocumented and
               unsupported feature which allowed the module argument
               for an apply operation to be a tuple: Var = dict:new(),
               Var:size(). This "feature" frequently caused confusion,
               especially when such call failed. The stacktrace would
               point out functions that don't exist in the source
               code.

               For legacy code that need to use parameterized modules
               or tuple calls for some other reason, there is a new
               compiler option called tuple_calls. When this option is
               given, the compiler will generate extra code that
               emulates the old behavior for calls where the module is
               a variable.


  OTP-14502    Application(s): erts

               *** HIGHLIGHT ***

               Creation of small maps with literal keys has been
               optimized to be faster and potentially use less memory.
               The keys are combined into a literal key tuple which is
               put into the literal pool. The key tuple can be shared
               between many instances of maps having the same keys.


  OTP-14508    Application(s): erts

               *** POTENTIAL INCOMPATIBILITY ***

               When an exception is thrown, include the arguments of
               the call in the stacktrace for BIFs band, bor, bsl,
               bsr, bxor, div, rem and the operators +, -, * and /.


  OTP-14518    Application(s): erts, otp

               *** HIGHLIGHT ***

               *** POTENTIAL INCOMPATIBILITY ***

               The non-smp emulators have been removed. This means
               that the configure options --disable-threads and
               --enable-plain-emulator have been removed and configure
               will now refuse to build Erlang/OTP on platforms
               without thread support.

               In order to achieve a similar setup as the non-smp
               emulator, it is possible to start Erlang/OTP with the
               +S 1 option.


  OTP-14575    Application(s): erts

               Modules that use floating point constants compiled with
               R15 or earlier will need to be re-compiled before they
               can be loaded.


  OTP-14589    Application(s): erts

               Implementation of true asynchronous signaling between
               processes in order to improve scalability. Signals
               affected include exit, monitor, demonitor, monitor
               triggered, link, unlink, and group leader.


  OTP-14604    Application(s): erts

               Added a PGO (profile guided optimization) pass to the
               build step of erts. This can be disabled by passing
               --disable-pgo to configure.


  OTP-14610    Application(s): erts
               Related Id(s): PR-1480

               Improved the performance of binary:split and
               binary:match.


  OTP-14613    Application(s): erts

               It is not longer possible to disable dirty schedulers
               when building erlang.


  OTP-14626    Application(s): compiler, erts

               *** HIGHLIGHT ***

               Loaded BEAM code in a 64-bit system requires less
               memory because of better packing of operands for
               instructions.

               These memory savings were achieved by major
               improvements to the beam_makeops scripts used when
               building the run time system and BEAM compiler. There
               is also new for documentation for beam_makeops that
               describes how new BEAM instructions and loader
               transformations can be implemented. The documentation
               is found in here in a source directory or git
               repository: erts/emulator/internal_doc/beam_makeops.md.
               An online version can be found here:
               https://github.com/erlang/otp/blob/master/erts/emulator/internal_doc/beam_makeops.md


  OTP-14637    Application(s): erts
               Related Id(s): ERL-327, PR-1524

               file:read_file has been changed to read the content of
               files that report a size of 0 even when data can be
               read from them. An example of such a file is
               /proc/cpuinfo on Linux.


  OTP-14651    Application(s): erts

               It is no longer possible to disable the temp_alloc
               allocator. Disabling it caused serious performance
               degradations and was never what was wanted.


  OTP-14667    Application(s): erts

               The reduction cost of sending messages is now constant.
               It will no longer scale according to the length of the
               receiving process' message queue.


  OTP-14680    Application(s): erts

               Improved loading of modules with -on_load directive, to
               no longer block all schedulers when the load operation
               is completed.


  OTP-14682    Application(s): erts

               On platforms with real-time signals available,
               SIGRTMIN+1 is now used as the internal scheduler
               suspend signal instead of SIGUSR2.


  OTP-14683    Application(s): compiler, erts

               When the value returned from a 'catch' expression is
               ignored, no stacktrace will be built if an exception is
               caught. That will save time and produce less garbage.
               There are also some minor optimizations of 'try/catch'
               both in the compiler and run-time system.


  OTP-14687    Application(s): erts

               The guarantees and non-guarantees of
               erlang:get_stacktrace/0 are now documented.


  OTP-14692    Application(s): compiler, erts

               *** HIGHLIGHT ***

               There is a new syntax in 'try/catch' for retrieving the
               stacktrace without calling 'erlang:get_stacktrace/0'.
               See the reference manual for a description of the new
               syntax. The 'erlang:get_stacktrace/0' BIF is now
               deprecated.


  OTP-14780    Application(s): erts

               New 'used' option for binary_to_term/2 that will also
               return number of bytes actually read from the binary.
               This enables easy access to any extra data in the
               binary located directly after the returned term.


  OTP-14795    Application(s): erts
               Related Id(s): ERL-88

               Added more statistics for
               erlang:system_info({allocator,A}) in the mbcs_pool
               section.


  OTP-14797    Application(s): erts

               Added enif_ioq_peek_head to retrieve Erlang terms from
               NIF IO queues without having to resort to copying.


  OTP-14830    Application(s): compiler, erts

               There is a new option 'makedep_side_effect' for the
               compiler and -MMD for 'erlc' that generates
               dependencies and continues to compile as normal.


  OTP-14884    Application(s): erts, stdlib

               Added ets:whereis/1 for retrieving the table identifier
               of a named table.


  OTP-14899    Application(s): erts, kernel

               *** HIGHLIGHT ***

               seq_trace labels may now be any erlang term.


  OTP-14901    Application(s): erts

               Optimized the common case of monitor followed by send
               to the same local process. The monitor signal is now
               delayed in order to be piggybacked with the sent
               message and thereby only get one lock operation on the
               message queue of the receiver. A delayed monitor signal
               is flushed if no send has been done at the latest when
               the process is scheduled out.


  OTP-14903    Application(s): erts, hipe

               Make hipe compiled code work on x86_64 (amd64) with OS
               security feature PIE, where executable code can be
               loaded into a random location. Old behavior, if hipe
               was enabled, was to disable PIE build options for the
               VM.


  OTP-14928    Application(s): erts

               *** HIGHLIGHT ***

               *** POTENTIAL INCOMPATIBILITY ***

               The number of driver async threads will now default to
               1 as the standard drivers do not use them anymore.
               Users that changed this value to tweak the file driver
               should replace +A with +SDio since it now uses dirty IO
               schedulers instead of async threads.


  OTP-14934    Application(s): erts
               Related Id(s): PR-1708

               Optimize == and /= for binaries with different sizes to
               be constant in time instead of proportional to the size
               of their common prefix.


  OTP-14948    Application(s): erts

               Refactorings making some internal process flags
               available for other usage.


  OTP-14951    Application(s): erts

               Removed need for HiPE to allocate native executable
               memory in low 2GB address space on x86_64. Command line
               option +MXscs is thereby obsolete and ignored.


  OTP-14954    Application(s): erts

               Added enif_make_map_from_arrays for creating a
               populated map, analogous to enif_make_list_from_array.


  OTP-14959    Application(s): erts

               Added configuration switches for busy-wait and wake up
               thresholds for dirty schedulers, and changing these
               settings for normal schedulers will no longer affect
               dirty schedulers.

               Refer to the documentation for details. The new
               switches are +sbwtdcpu, +sbwtdio, +swtdcpu, and
               +swtdio.

               The default busy wait threshold for dirty scheduler
               threads has also been lowered to short.


  OTP-14960    Application(s): erts

               The list of "taints" now also includes dynamic loaded
               drivers in addition to NIF libraries. Statically linked
               drivers and NIF libraries that are part of erts are not
               included. The "taints" are returned by
               system_info(taints) and printed in the header of
               erl_crash.dump files.


  OTP-14961    Application(s): erts, tools

               *** POTENTIAL INCOMPATIBILITY ***

               Added instrument:allocations and instrument:carriers
               for retrieving information about memory utilization and
               fragmentation.

               The old instrument interface has been removed, as have
               the related options +Mim and +Mis.


  OTP-14964    Application(s): erts
               Related Id(s): OTP-14589

               *** POTENTIAL INCOMPATIBILITY ***

               The process suspend functionality used by the
               erlang:suspend_process/2 BIF has been reimplemented
               using the newly introduced true asynchronous signaling
               between processes. This mainly to reduce memory usage
               in the process control block of all processes, but also
               in order to simplify the implementation.

               WARNING: You can easily create deadlocks if processes
               suspends each other (directly or in circles). In ERTS
               versions prior to ERTS version 10.0, the runtime system
               prevented such deadlocks, but this prevention has now
               been removed due to performance reasons.

               Other ERTS internal functionality that used the
               previous process suspend functionality have also been
               reimplemented to use asynchronous signaling instead.


  OTP-14965    Application(s): erts

               Added the nifs option to ?MODULE:module_info/1 for
               listing a module's installed NIF functions.


  OTP-14966    Application(s): erts

               New implementation of erlang:process_info/[1,2].

               In the general case when inspecting another process,
               the new implementation sends an asynchronous
               process-info request signal to the other process and
               waits for the result instead of locking the other
               process and reading the result directly. In some
               special cases where no conflicts occur, signal order
               wont be violated, and the amount of data requested is
               guaranteed to be small, the inspected process may be
               inspected directly.

               Appropriate amount of reductions are now also bumped
               when inspecting a process.


  OTP-14975    Application(s): erts
               Related Id(s): PR-1597

               Removed process start time from crash dump in order to
               save memory in process control block.


  OTP-14976    Application(s): erts

               Optimize erlang:put/2 when updating existing key with a
               new immediate value (atom, small integer, pid, port).


  OTP-14986    Application(s): erts
               Related Id(s): PR-1745

               *** POTENTIAL INCOMPATIBILITY ***

               erlang:process_info/1 has been changed to no longer
               include messages by default. Instead
               erlang:process_info/2 should be used.


  OTP-14994    Application(s): erts

               New NIF functions: enif_mutex_name, enif_cond_name,
               enif_rwlock_name, enif_thread_name, enif_vfprintf,
               enif_vsnprintf.


  OTP-15026    Application(s): erts

               When erlang:system_flag(backtrace_depth, 0) has been
               called, all exceptions will now contain the entry for
               *one* function (despite the zero). It used to be that a
               hand-made stack backtrace passed to erlang:raise/3
               would be be truncated to an empty list.


  OTP-15031    Application(s): erts

               Fixed bug for named ets tables which could cause
               unexpected results from matchspec iteration functions
               (ets:select* and ets:match*) if the table was deleted
               and recreated with the same name during the iteration.
               The iteration could incorrectly continue through the
               recreated table. The expected correct behavior is now
               for the iteration call to fail with a badarg exception
               if the table is deleted before the iteration has
               completed.


  OTP-15037    Application(s): compiler, erts
               Related Id(s): PR-1784, PR-1802

               *** HIGHLIGHT ***

               Two new guards BIFs operating on maps have been added:
               map_get/2 and is_map_key/2. They do the same as
               maps:get/2 and maps:is_key/2, respectively, except that
               they are allowed to be used in guards.


  OTP-15081    Application(s): erts

               Release run-queue lock while cleaning up terminated
               dirty process.


  OTP-15086    Application(s): erts, kernel
               Related Id(s): PR-1694

               The callback module passed as -epmd_module to erl has
               been expanded to be able to do name and port resolving.

               Documentation has also been added in the erl_epmd
               reference manual and ERTS User's Guide How to Implement
               an Alternative Service Discovery for Erlang
               Distribution.


 Full runtime dependencies of erts-10.0: kernel-6.0, sasl-3.0.1,
 stdlib-3.5


 ---------------------------------------------------------------------
 --- et-1.6.2 --------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14861    Application(s): et, eunit, mnesia, parsetools, reltool

               Calls to erlang:get_stacktrace() are removed.


 Full runtime dependencies of et-1.6.2: erts-9.0, kernel-5.3,
 runtime_tools-1.10, stdlib-3.4, wx-1.2


 ---------------------------------------------------------------------
 --- eunit-2.3.6 -----------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14861    Application(s): et, eunit, mnesia, parsetools, reltool

               Calls to erlang:get_stacktrace() are removed.


 Full runtime dependencies of eunit-2.3.6: erts-9.0, kernel-5.3,
 stdlib-3.4


 ---------------------------------------------------------------------
 --- ftp-1.0 ---------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14113    Application(s): inets

               Split inets and create separate ftp and tftp apps.


 Full runtime dependencies of ftp-1.0: erts-7.0, kernel-6.0,
 stdlib-3.5


 ---------------------------------------------------------------------
 --- hipe-3.18 -------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14785    Application(s): hipe
               Related Id(s): PR-1632

               Optimize receive statements that are only waiting for
               messages containing a reference created before the
               receive. All messages that existed in the queue when
               the reference was created will be bypassed, as they
               cannot possibly contain the reference. This
               optimization has existed for vanilla BEAM since OTP
               R14.


  OTP-14900    Application(s): hipe
               Related Id(s): PR-1621, PR-1685

               Add validation pass to hipe compiler to detect internal
               errors causing primop calls that may trigger an unsafe
               GC at run-time. The pass can be disabled with option
               no_verify_gcsafe.


  OTP-14903    Application(s): erts, hipe

               Make hipe compiled code work on x86_64 (amd64) with OS
               security feature PIE, where executable code can be
               loaded into a random location. Old behavior, if hipe
               was enabled, was to disable PIE build options for the
               VM.


  OTP-14941    Application(s): hipe
               Related Id(s): PR-1718

               Inline more type test BIFs; is_number, is_bitstring,
               is_map.


 Full runtime dependencies of hipe-3.18: compiler-5.0, erts-9.3,
 kernel-5.3, stdlib-3.4, syntax_tools-1.6.14


 ---------------------------------------------------------------------
 --- inets-7.0 -------------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14726    Application(s): inets

               Fixed HTTP content injection bug in httpc (ERL-456).


  OTP-14729    Application(s): inets

               Fixed support for URI-references in HTTP 'Location'
               header (ERL-333).


  OTP-15006    Application(s): inets

               Fix broken 'Content-Type' handling in httpc (ERL-536).


  OTP-15021    Application(s): inets

               Fix handling of relative paths in the script_alias
               property of httpd (ERL-574).


  OTP-15025    Application(s): inets

               Fix httpd:reload_config/2 with path() as the first
               argument (ERL-578).


  OTP-15042    Application(s): inets

               Improved gracefulness.


 --- Improvements and New Features ---

  OTP-14113    Application(s): inets

               Split inets and create separate ftp and tftp apps.


 Full runtime dependencies of inets-7.0: erts-6.0, kernel-3.0,
 mnesia-4.12, runtime_tools-1.8.14, ssl-5.3.4, stdlib-3.5


 ---------------------------------------------------------------------
 --- jinterface-1.9 --------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14844    Application(s): jinterface

               Add module package name for Java 9


 ---------------------------------------------------------------------
 --- kernel-6.0 ------------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-10551    Application(s): kernel

               Clarify the documentation of rpc:multicall/5.


  OTP-13133    Application(s): kernel
               Related Id(s): PR-1557

               The DNS resolver when getting econnrefused from a
               server retained an invalid socket so look up towards
               the next server(s) also failed.


  OTP-13761    Application(s): kernel
               Related Id(s): ERL-503

               *** POTENTIAL INCOMPATIBILITY ***

               No resolver backend returns V4Mapped IPv6 addresses any
               more. This was inconsistent before, some did, some did
               not. To facilitate working with such addresses a new
               function inet:ipv4_mapped_ipv6_address/1 has been
               added.


  OTP-14019    Application(s): erts, kernel, stdlib
               Related Id(s): ERL-550

               The type specifications for file:posix/0 and
               inet:posix/0 have been updated according to which
               errors file and socket operations should be able to
               return.


  OTP-14501    Application(s): kernel

               Fix name resolving in IPv6 only environments when doing
               the initial distributed connection.


  OTP-14543    Application(s): erts, kernel, stdlib
               Related Id(s): ERL-370

               *** POTENTIAL INCOMPATIBILITY ***

               File operations used to accept filenames containing
               null characters (integer value zero). This caused the
               name to be truncated and in some cases arguments to
               primitive operations to be mixed up. Filenames
               containing null characters inside the filename are now
               *rejected* and will cause primitive file operations to
               fail.

               Also environment variable operations used to accept
               names and values of environment variables containing
               null characters (integer value zero). This caused
               operations to silently produce erroneous results.
               Environment variable names and values containing null
               characters inside the name or value are now *rejected*
               and will cause environment variable operations to fail.

               Primitive environment variable operations also used to
               accept the $= character in environment variable names
               causing various problems. $= characters in environment
               variable names are now also *rejected*.

               Also os:cmd/1 now reject null characters inside its
               command.

               erlang:open_port/2 will also reject null characters
               inside the port name from now on.


  OTP-14666    Application(s): erts, kernel

               *** POTENTIAL INCOMPATIBILITY ***

               os:putenv and os:getenv no longer access the process
               environment directly and instead work on a thread-safe
               emulation. The only observable difference is that it's
               *not* kept in sync with libc getenv(3) / putenv(3), so
               those who relied on that behavior in drivers or NIFs
               will need to add manual synchronization.

               On Windows this means that you can no longer resolve
               DLL dependencies by modifying the PATH just before
               loading the driver/NIF. To make this less of a problem,
               the emulator now adds the target DLL's folder to the
               DLL search path.


  OTP-14681    Application(s): kernel

               Fixed connection tick toward primitive hidden nodes
               (erl_interface) that could cause faulty tick timeout in
               rare cases when payload data is sent to hidden node but
               not received.


  OTP-14991    Application(s): kernel
               Related Id(s): PR1705

               Make group react immediately on an EXIT-signal from
               shell in e.g ssh.


  OTP-15001    Application(s): erts, kernel

               Calls to gen_tcp:send/2 on closed sockets now returns
               {error, closed} instead of {error,enotconn}.


  OTP-15071    Application(s): kernel

               *** POTENTIAL INCOMPATIBILITY ***

               The included_applications key are no longer duplicated
               as application environment variable. Earlier, the
               included applications could be read both with
               application:get[_all]_env(...) and
               application:get[_all]_key(...) functions. Now, it can
               only be read with application:get[_all]_key(...).


 --- Improvements and New Features ---

  OTP-13295    Application(s): erts, kernel, sasl, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               A new logging API is added to Erlang/OTP, see the
               logger(3) manual page, and section Logging in the
               Kernel User's Guide.

               Calls to error_logger are automatically redirected to
               the new API, and legacy error logger event handlers can
               still be used. It is, however, recommended to use the
               Logger API directly when writing new code.

               Notice the following potential incompatibilities:

               -- Kernel configuration parameters error_logger still
               works, but is overruled if the default handler's output
               destination is configured with Kernel configuration
               parameter logger.

               In general, parameters for configuring error logger are
               overwritten by new parameters for configuring Logger.

               -- The concept of SASL error logging is deprecated,
               meaning that by default the SASL application does not
               affect which log events are logged.

               By default, supervisor reports and crash reports are
               logged by the default Logger handler started by Kernel,
               and end up at the same destination (terminal or file)
               as other standard log event from Erlang/OTP.

               Progress reports are not logged by default, but can be
               enabled with the Kernel configuration parameter
               logger_progress_reports.

               To obtain backwards compatibility with the SASL error
               logging functionality from earlier releases, set Kernel
               configuration parameter logger_sasl_compatible to true.
               This prevents the default Logger handler from logging
               any supervisor-, crash-, or progress reports. Instead,
               SASL adds a separate Logger handler during application
               start, which takes care of these log events. The SASL
               configuration parameters sasl_error_logger and
               sasl_errlog_type specify the destination (terminal or
               file) and severity level to log for these events.


  OTP-13713    Application(s): kernel
               Related Id(s): PR-1645

               The function inet:i/0 has been documented.


  OTP-14359    Application(s): kernel
               Related Id(s): PR-1816

               Typespecs for netns and bind_to_device options have
               been added to gen_tcp, gen_udp and gen_sctp functions.


  OTP-14459    Application(s): erts, kernel

               *** HIGHLIGHT ***

               New functionality for implementation of alternative
               carriers for the Erlang distribution has been
               introduced. This mainly consists of support for usage
               of distribution controller processes (previously only
               ports could be used as distribution controllers). For
               more information see ERTS User's Guide ➜ How to
               implement an Alternative Carrier for the Erlang
               Distribution ➜ Distribution Module.


  OTP-14899    Application(s): erts, kernel

               *** HIGHLIGHT ***

               seq_trace labels may now be any erlang term.


  OTP-14969    Application(s): kernel, ssl
               Related Id(s): ERL-598, OTP-14465

               The SSL distribution protocol -proto inet_tls has
               stopped setting the SSL option server_name_indication.
               New verify funs for client and server in inet_tls_dist
               has been added, not documented yet, that checks node
               name if present in peer certificate. Usage is still
               also yet to be documented.


  OTP-15009    Application(s): kernel
               Related Id(s): ERL-601

               Changed timeout of gen_server calls to auth server from
               default 5 seconds to infinity.


  OTP-15086    Application(s): erts, kernel
               Related Id(s): PR-1694

               The callback module passed as -epmd_module to erl has
               been expanded to be able to do name and port resolving.

               Documentation has also been added in the erl_epmd
               reference manual and ERTS User's Guide How to Implement
               an Alternative Service Discovery for Erlang
               Distribution.


 Full runtime dependencies of kernel-6.0: erts-10.0, sasl-3.0,
 stdlib-3.5


 ---------------------------------------------------------------------
 --- mnesia-4.15.4 ---------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14861    Application(s): et, eunit, mnesia, parsetools, reltool

               Calls to erlang:get_stacktrace() are removed.


 Full runtime dependencies of mnesia-4.15.4: erts-9.0, kernel-5.3,
 stdlib-3.4


 ---------------------------------------------------------------------
 --- observer-2.8 ----------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14993    Application(s): observer
               Related Id(s): PR-1666

               Added possibility to garbage collect selected processes
               and fixed a crash when the saved config file contained
               bad data.


 --- Improvements and New Features ---

  OTP-14902    Application(s): common_test, observer, public_key, ssl

               Use uri_string module instead of http_uri.


 Full runtime dependencies of observer-2.8: erts-7.0, et-1.5,
 kernel-3.0, runtime_tools-1.8.14, stdlib-3.5, wx-1.2


 ---------------------------------------------------------------------
 --- os_mon-2.4.5 ----------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14513    Application(s): os_mon

               Fix disksup to handle mount paths with spaces in them.


 Full runtime dependencies of os_mon-2.4.5: erts-6.0, kernel-3.0,
 mnesia-4.12, otp_mibs-1.0.9, sasl-2.4, snmp-4.25.1, stdlib-2.0


 ---------------------------------------------------------------------
 --- parsetools-2.1.7 ------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14861    Application(s): et, eunit, mnesia, parsetools, reltool

               Calls to erlang:get_stacktrace() are removed.


 Full runtime dependencies of parsetools-2.1.7: erts-6.0, kernel-3.0,
 stdlib-2.5


 ---------------------------------------------------------------------
 --- public_key-1.6 --------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14788    Application(s): public_key
               Related Id(s): OTP-14624

               Update calls to the base64 module to conform to that
               module's type specifications.


 --- Improvements and New Features ---

  OTP-14902    Application(s): common_test, observer, public_key, ssl

               Use uri_string module instead of http_uri.


  OTP-15093    Application(s): public_key

               Compleate PKCS-8 encoding support and enhance the
               decoding of 'PrivateKeyInfo' to conform to the rest of
               Erlang public_key API.


 Full runtime dependencies of public_key-1.6: asn1-3.0, crypto-3.8,
 erts-6.0, kernel-3.0, stdlib-3.5


 ---------------------------------------------------------------------
 --- reltool-0.7.6 ---------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14861    Application(s): et, eunit, mnesia, parsetools, reltool

               Calls to erlang:get_stacktrace() are removed.


 Full runtime dependencies of reltool-0.7.6: erts-7.0, kernel-3.0,
 sasl-2.4, stdlib-3.4, tools-2.6.14, wx-1.2


 ---------------------------------------------------------------------
 --- runtime_tools-1.13 ----------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14904    Application(s): runtime_tools

               New utility module scheduler which makes it easier to
               measure scheduler utilization.


 Full runtime dependencies of runtime_tools-1.13: erts-8.0,
 kernel-5.0, mnesia-4.12, stdlib-3.0


 ---------------------------------------------------------------------
 --- sasl-3.2 --------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-13295    Application(s): erts, kernel, sasl, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               A new logging API is added to Erlang/OTP, see the
               logger(3) manual page, and section Logging in the
               Kernel User's Guide.

               Calls to error_logger are automatically redirected to
               the new API, and legacy error logger event handlers can
               still be used. It is, however, recommended to use the
               Logger API directly when writing new code.

               Notice the following potential incompatibilities:

               -- Kernel configuration parameters error_logger still
               works, but is overruled if the default handler's output
               destination is configured with Kernel configuration
               parameter logger.

               In general, parameters for configuring error logger are
               overwritten by new parameters for configuring Logger.

               -- The concept of SASL error logging is deprecated,
               meaning that by default the SASL application does not
               affect which log events are logged.

               By default, supervisor reports and crash reports are
               logged by the default Logger handler started by Kernel,
               and end up at the same destination (terminal or file)
               as other standard log event from Erlang/OTP.

               Progress reports are not logged by default, but can be
               enabled with the Kernel configuration parameter
               logger_progress_reports.

               To obtain backwards compatibility with the SASL error
               logging functionality from earlier releases, set Kernel
               configuration parameter logger_sasl_compatible to true.
               This prevents the default Logger handler from logging
               any supervisor-, crash-, or progress reports. Instead,
               SASL adds a separate Logger handler during application
               start, which takes care of these log events. The SASL
               configuration parameters sasl_error_logger and
               sasl_errlog_type specify the destination (terminal or
               file) and severity level to log for these events.


  OTP-14469    Application(s): sasl

               *** POTENTIAL INCOMPATIBILITY ***

               The old and outdated "Status Inspection" tool (modules
               si and si_sasl_sup) is removed.


  OTP-14950    Application(s): sasl
               Related Id(s): PR-1560

               When creating the release tar file, systools now
               includes sys.config.src if it exists in the
               $ROOT/releases/<vsn>/ directory. This is to allow
               adjustments, e.g. resolving environment variables,
               after unpacking the release, but before installing it.
               This functionality requires a custom tool which uses
               sys.config.src as input and creates a correct
               sys.config file.


 Full runtime dependencies of sasl-3.2: erts-9.0, kernel-5.3,
 stdlib-3.4, tools-2.6.14


 ---------------------------------------------------------------------
 --- ssh-4.7 ---------------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14880    Application(s): ssh

               Updated ssh_connection:shell/2 documentation.


  OTP-14955    Application(s): ssh

               If the daemon port listener is restarted, it could
               potentially fail with eaddrinuse if the timing is
               unlucky. It will now retry and exponentially back off
               the listener restart a few times before failing.


  OTP-15084    Application(s): ssh

               A channel callback module always got the module name as
               reason in a call to terminate. Now it will get the
               proper Reason, usually 'normal'.


 --- Improvements and New Features ---

  OTP-14851    Application(s): ssh

               *** POTENTIAL INCOMPATIBILITY ***

               An option exec for daemons implementing the 'exec' has
               existed a long time but has been undocumented. The old
               behaviour is kept for compatibility EXCEPT that error
               messages are changed and are sent as "stderror" text.

               A new option value is defined to make it much more easy
               to implement an own exec server.


  OTP-14896    Application(s): ssh

               The undocumented ssh_dbg module is completely
               re-written to facilitate tracing/debugging.


  OTP-14988    Application(s): ssh

               The SSH supervisor structure has been slightly changed.
               This makes stopping the ssh application considerably
               faster if there are open connections. This is important
               in for example restarts.


  OTP-15002    Application(s): ssh
               Related Id(s): OTP-15030

               *** POTENTIAL INCOMPATIBILITY ***

               The type specifications in SSH are reworked and the
               following types are renamed:

               ssh:ssh_connection_ref() is changed to
               ssh:connection_ref(),

               ssh:ssh_daemon_ref() is changed to ssh:daemon_ref(),

               ssh:ssh_channel_id() is changed to ssh:channel_id().


  OTP-15019    Application(s): ssh

               The internal timer handling in SSH is now based on the
               gen_statem timers.


  OTP-15028    Application(s): ssh

               Removed unused ssh_client_key.erl and
               ssh_server_key.erl.


  OTP-15030    Application(s): ssh
               Related Id(s): OTP-15002

               The Reference Manual pages are partly updated.

               The ssh page is now generated from specs and types, is
               restructured and is partly rephrased.

               The ssh_channel, ssh_connection, ssh_client_key_api,
               ssh_server_key_api and ssh_sftp pages are updated with
               links, correct type names and some minor changes.


  OTP-15041    Application(s): ssh

               The behaviors ssh_channel and ssh_daemon_channel are
               renamed to ssh_client_channel and ssh_server_channel
               respectively.

               The old modules are kept for compatibility but should
               preferably be replaced when updating callback modules
               referring them.


  OTP-15069    Application(s): ssh
               Related Id(s): ERL-617

               The rekey_limit option could now set the max time as
               well as the previously max data amount.


  OTP-15082    Application(s): ssh

               Change process exit supervision with monitor instead of
               link


 Full runtime dependencies of ssh-4.7: crypto-4.2, erts-6.0,
 kernel-3.0, public_key-1.5.2, stdlib-3.3


 ---------------------------------------------------------------------
 --- ssl-9.0 ---------------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14974    Application(s): ssl

               Correct handling of ECDH suites.


  OTP-15050    Application(s): ssl

               Proper handling of clients that choose to send an empty
               answer to a certificate request


 --- Improvements and New Features ---

  OTP-14465    Application(s): ssl

               Distribution over SSL (inet_tls) has, to improve
               performance, been rewritten to not use intermediate
               processes and ports.


  OTP-14547    Application(s): ssl

               Add suport for ECDHE_PSK cipher suites


  OTP-14768    Application(s): ssl

               *** INCOMPATIBILITY with possibly ***

               For security reasons no longer support 3-DES cipher
               suites by default


  OTP-14769    Application(s): ssl

               *** INCOMPATIBILITY with possible ***

               For security reasons RSA-key exchange cipher suites are
               no longer supported by default


  OTP-14789    Application(s): ssl

               *** INCOMPATIBILITY with possibly ***

               The interoperability option to fallback to insecure
               renegotiation now has to be explicitly turned on.


  OTP-14824    Application(s): ssl

               *** POTENTIAL INCOMPATIBILITY ***

               Drop support for SSLv2 enabled clients. SSLv2 has been
               broken for decades and never supported by the Erlang
               SSL/TLS implementation. This option was by default
               disabled and enabling it has proved to sometimes break
               connections not using SSLv2 enabled clients.


  OTP-14882    Application(s): ssl

               *** INCOMPATIBILITY with possibly ***

               Remove CHACHA20_POLY1305 ciphers form default for now.
               We have discovered interoperability problems, ERL-538,
               that we believe needs to be solved in crypto.


  OTP-14888    Application(s): ssl

               Generalize DTLS packet multiplexing to make it easier
               to add future DTLS features and uses.


  OTP-14902    Application(s): common_test, observer, public_key, ssl

               Use uri_string module instead of http_uri.


  OTP-14969    Application(s): kernel, ssl
               Related Id(s): ERL-598, OTP-14465

               The SSL distribution protocol -proto inet_tls has
               stopped setting the SSL option server_name_indication.
               New verify funs for client and server in inet_tls_dist
               has been added, not documented yet, that checks node
               name if present in peer certificate. Usage is still
               also yet to be documented.


  OTP-15056    Application(s): ssl

               Deprecate ssl:ssl_accept/[1,2,3] in favour of
               ssl:handshake/[1,2,3]


 Full runtime dependencies of ssl-9.0: crypto-4.2, erts-10.0,
 inets-5.10.7, kernel-6.0, public_key-1.5, stdlib-3.5


 ---------------------------------------------------------------------
 --- stdlib-3.5 ------------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-14015    Application(s): stdlib

               gen_statem improvements.

               When using an exception that is valid but not allowed
               in a state enter call, the reason has been changed from
               {bad_action_from_state_function,Action} to
               {bad_state_enter_action_from_state_function,Action}.

               Timer parsing has been improved. Many erroneous timeout
               tuples was not handled correctly.

               The documentation has been updated, in particular the
               User's Guide and the pointer to it from the Reference
               Manual is much more obvious.


  OTP-14019    Application(s): erts, kernel, stdlib
               Related Id(s): ERL-550

               The type specifications for file:posix/0 and
               inet:posix/0 have been updated according to which
               errors file and socket operations should be able to
               return.


  OTP-14543    Application(s): erts, kernel, stdlib
               Related Id(s): ERL-370

               *** POTENTIAL INCOMPATIBILITY ***

               File operations used to accept filenames containing
               null characters (integer value zero). This caused the
               name to be truncated and in some cases arguments to
               primitive operations to be mixed up. Filenames
               containing null characters inside the filename are now
               *rejected* and will cause primitive file operations to
               fail.

               Also environment variable operations used to accept
               names and values of environment variables containing
               null characters (integer value zero). This caused
               operations to silently produce erroneous results.
               Environment variable names and values containing null
               characters inside the name or value are now *rejected*
               and will cause environment variable operations to fail.

               Primitive environment variable operations also used to
               accept the $= character in environment variable names
               causing various problems. $= characters in environment
               variable names are now also *rejected*.

               Also os:cmd/1 now reject null characters inside its
               command.

               erlang:open_port/2 will also reject null characters
               inside the port name from now on.


  OTP-14958    Application(s): stdlib
               Related Id(s): PR-1735

               Make io_lib:unscan_format/1 work with pad char and
               default precision.


  OTP-14971    Application(s): stdlib
               Related Id(s): PR-1743

               The control sequence modifiers t and l can be used
               together in the same control sequence which makes it
               possible to have Unicode atoms and no detection of
               printable character lists at the same time.


  OTP-15035    Application(s): stdlib
               Related Id(s): ERL-613

               Fix a bug in the Erlang code linter: the check of guard
               expressions no longer returns false if the map syntax
               is used. The bug affected the Erlang shell, the
               Debugger, and other modules evaluating abstract code.


  OTP-15049    Application(s): stdlib

               A sys debug fun of type {Fun,State} should not be
               possible to install twice. This was, however, possible
               if the current State was 'undefined', which was
               mistaken for non-existing fun. This has been corrected.


 --- Improvements and New Features ---

  OTP-13019    Application(s): stdlib
               Related Id(s): PR-1490

               The gen_server has gotten a new callback
               handle_continue/2 for check pointing the state. This is
               useful at least when implementing behaviours on top of
               gen_server and for some start up scenarios.


  OTP-13073    Application(s): stdlib
               Related Id(s): PR-1595

               *** POTENTIAL INCOMPATIBILITY ***

               The semantics of timeout parameter
               {clean_timeout,infinity} to gen_statem:call/3 has been
               changed to use a proxy process for the call. With this
               change clean_timeout implicates a proxy process with no
               exceptions. This may be a hard to observe
               incompatibility: in the presence of network problems a
               late reply could arrive in the caller's message queue
               when catching errors. That will not happen after this
               correction.

               The semantics of timeout parameter infinity has not
               been changed.


  OTP-13295    Application(s): erts, kernel, sasl, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               A new logging API is added to Erlang/OTP, see the
               logger(3) manual page, and section Logging in the
               Kernel User's Guide.

               Calls to error_logger are automatically redirected to
               the new API, and legacy error logger event handlers can
               still be used. It is, however, recommended to use the
               Logger API directly when writing new code.

               Notice the following potential incompatibilities:

               -- Kernel configuration parameters error_logger still
               works, but is overruled if the default handler's output
               destination is configured with Kernel configuration
               parameter logger.

               In general, parameters for configuring error logger are
               overwritten by new parameters for configuring Logger.

               -- The concept of SASL error logging is deprecated,
               meaning that by default the SASL application does not
               affect which log events are logged.

               By default, supervisor reports and crash reports are
               logged by the default Logger handler started by Kernel,
               and end up at the same destination (terminal or file)
               as other standard log event from Erlang/OTP.

               Progress reports are not logged by default, but can be
               enabled with the Kernel configuration parameter
               logger_progress_reports.

               To obtain backwards compatibility with the SASL error
               logging functionality from earlier releases, set Kernel
               configuration parameter logger_sasl_compatible to true.
               This prevents the default Logger handler from logging
               any supervisor-, crash-, or progress reports. Instead,
               SASL adds a separate Logger handler during application
               start, which takes care of these log events. The SASL
               configuration parameters sasl_error_logger and
               sasl_errlog_type specify the destination (terminal or
               file) and severity level to log for these events.


  OTP-13413    Application(s): stdlib

               Add functions calendar:system_time_to_local_time/2 and
               calendar:system_time_to_universal_time/2.


  OTP-13764    Application(s): stdlib
               Related Id(s): PR-1574

               Functions rand:uniform_real/0 and rand:uniform_real_s/1
               have been added. They produce uniformly distributed
               numbers in the range 0.0 =< X < 1.0 that are as close
               to random real numbers as Normalized IEEE 754 Double
               Precision allows. Because the random real number
               exactly 0.0 is infinitely improbable they will never
               return exactly 0.0.

               These properties are useful when you need to call for
               example math:log(X) or 1 / X on a random value X, since
               that will never fail with a number from these new
               functions.


  OTP-14012    Application(s): stdlib

               Added maps:iterator/0 and maps:next/1 to be used for
               iterating over the key-value associations in a map.


  OTP-14439    Application(s): compiler, dialyzer, erts, stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               Changed the default behaviour of .erlang loading:
               .erlang is no longer loaded from the current directory.
               c:erlangrc(PathList) can be used to search and load an
               .erlang file from user specified directories.

               escript, erlc, dialyzer and typer no longer load an
               .erlang at all.


  OTP-14496    Application(s): stdlib

               Added new uri_string module to stdlib for handling URIs
               (RFC 3986).


  OTP-14503    Application(s): stdlib

               Update Unicode specification to version 10.0.


  OTP-14577    Application(s): stdlib

               *** POTENTIAL INCOMPATIBILITY ***

               filelib:wildcard() now allows characters with a special
               meaning to be escaped using backslashes.

               This is an incompatible change, but note that the use
               of backslashes in wildcards would already work
               differently on Windows and Unix. Existing calls to
               filelib:wildcard() needs to be updated. On Windows,
               directory separators must always be written as a slash.


  OTP-14586    Application(s): stdlib

               The supervisor now stores its child specifications in a
               map instead of a list. This causes a significant
               improvement when starting many children under a
               non-simple_one_for_one supervisor.


  OTP-14624    Application(s): stdlib
               Related Id(s): PR-1565

               The base64 module is optimized.

               Note that the functions encode/1, decode/1, and
               mime_decode/1 fail unless called with an argument of
               the documented type. They used to accept any iodata().


  OTP-14675    Application(s): stdlib
               Related Id(s): PR-102

               Add function lists:search/2.


  OTP-14747    Application(s): stdlib

               uri_string module extended with functions for handling
               application/x-www-form-urlencoded query strings based
               on the HTML5 specification.


  OTP-14764    Application(s): stdlib

               Add functions calendar:rfc3339_to_system_time/1,2 and
               calendar:system_time_to_rfc3339/1,2.


  OTP-14826    Application(s): stdlib
               Related Id(s): 1540, PR

               The stack traces returned by the functions of the
               erl_eval module more accurately reflect where the
               exception occurred.


  OTP-14834    Application(s): stdlib
               Related Id(s): 1608, PR

               Add options atime, mtime, ctime, uid, and gid to the
               erl_tar:add/3,4 functions.


  OTP-14884    Application(s): erts, stdlib

               Added ets:whereis/1 for retrieving the table identifier
               of a named table.


  OTP-14910    Application(s): stdlib

               Improved URI normalization functions in the uri_string
               module.


  OTP-14983    Application(s): stdlib

               The new functions io_lib:fwrite/3 and io_lib:format/3
               take a third argument, an option list. The only option
               is chars_limit, which is used for limiting the number
               of returned characters. The limit is soft, which means
               that the number of returned characters exceeds the
               limit with at most a smallish amount. If the limit is
               set, the functions format/3 and fwrite/3 try to
               distribute the number of characters evenly over the
               control sequences pPswW. Furthermore, the control
               sequences pPwP try to distribute the number of
               characters evenly over substructures.

               A modification of the control sequences pPwW is that
               even if there is no limit on the number of returned
               characters, all associations of a map are printed to
               the same depth. The aim is to give a more consistent
               output as the order of map keys is not defined. As
               before, if the depth is less than the number of
               associations of a map, the selection of associations to
               print is arbitrary.


  OTP-14996    Application(s): stdlib
               Related Id(s): ERL-557, PR-1703

               Add functions ordsets:is_empty/1 and sets:is_empty/1.


  OTP-14998    Application(s): stdlib

               Improve performance of string:uppercase/1,
               string:lowercase/1 and string:casefold/1 when handling
               ASCII characters.


  OTP-15003    Application(s): compiler, stdlib

               External funs with literal values for module, name, and
               arity (e.g. erlang:abs/1) are now treated as literals.
               That means more efficient code that produces less
               garbage on the heap.


  OTP-15047    Application(s): stdlib

               sys:statistics(Pid,get) did not report 'out' messages
               from gen_server. This is now corrected.


  OTP-15048    Application(s): stdlib

               A sys debug function can now have the format
               {Id,Fun,State} in addition to the old {Fun,State}. This
               allows installing multiple instances of a debug fun.


  OTP-15072    Application(s): stdlib
               Related Id(s): 1786, PR

               *** POTENTIAL INCOMPATIBILITY ***

               The lib module is removed:

               -- lib:error_message/2 is removed.

               -- lib:flush_receive/0 is removed.

               -- lib:nonl/1 is removed.

               -- lib:progname/0 is replaced by ct:get_progname/0.

               -- lib:send/2 is removed.

               -- lib:sendw/2 is removed.


  OTP-15078    Application(s): stdlib

               Function ets:delete_all_objects/1 now yields the
               scheduler thread for large tables that take significant
               time to clear. This to improve real time
               characteristics of other runnable processes.


 Full runtime dependencies of stdlib-3.5: compiler-5.0, crypto-3.3,
 erts-10.0, kernel-6.0, sasl-3.0


 ---------------------------------------------------------------------
 --- syntax_tools-2.1.5 ----------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-15036    Application(s): asn1, edoc, eldap, syntax_tools

               Update to use the new string api instead of the old.


 Full runtime dependencies of syntax_tools-2.1.5: compiler-7.0,
 erts-9.0, kernel-5.0, stdlib-3.4


 ---------------------------------------------------------------------
 --- tftp-1.0 --------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14113    Application(s): inets

               Split inets and create separate ftp and tftp apps.


 Full runtime dependencies of tftp-1.0: kernel-6.0, stdlib-3.5


 ---------------------------------------------------------------------
 --- tools-3.0 -------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-14961    Application(s): erts, tools

               *** POTENTIAL INCOMPATIBILITY ***

               Added instrument:allocations and instrument:carriers
               for retrieving information about memory utilization and
               fragmentation.

               The old instrument interface has been removed, as have
               the related options +Mim and +Mis.


 Full runtime dependencies of tools-3.0: compiler-5.0, erts-9.1,
 kernel-5.4, runtime_tools-1.8.14, stdlib-3.4


 ---------------------------------------------------------------------
 --- wx-1.8.4 --------------------------------------------------------
 ---------------------------------------------------------------------

 --- Improvements and New Features ---

  OTP-15027    Application(s): wx

               Changed implementation so wx can now be built towards
               wxWidgets-3.1.1.


 Full runtime dependencies of wx-1.8.4: erts-6.0, kernel-3.0,
 stdlib-2.0


 ---------------------------------------------------------------------
 --- xmerl-1.3.17 ----------------------------------------------------
 ---------------------------------------------------------------------

 --- Fixed Bugs and Malfunctions ---

  OTP-15039    Application(s): xmerl

               Fix typos in documentation.


 Full runtime dependencies of xmerl-1.3.17: erts-6.0, kernel-3.0,
 stdlib-2.5


 ---------------------------------------------------------------------
 ---------------------------------------------------------------------
 ---------------------------------------------------------------------