[appendix]
== Migrating from Gun 2.0 to 2.1

Gun 2.1 contains a small security improvement for
the HTTP/2 protocol, as well as includes a small
number of fixes and improvements.

Gun 2.1 requires Erlang/OTP 22.0 or greater.

=== Features added

* A new HTTP/2 option `max_fragmented_header_block_size` has
  been added to limit the size of header blocks that are
  sent over multiple HEADERS and CONTINUATION frames.

* Update Cowlib to 2.13.0.

=== Bugs fixed

* Gun will no longer configure the NPN TLS extension,
  which has long been replaced by ALPN. NPN is not
  compatible with TLS 1.3.

* Gun will no longer crash when TLS connections close
  very early in the connection's life time.