[appendix]
== Migrating from Cowboy 2.11 to 2.12

Cowboy 2.12 contains a small security improvement for
the HTTP/2 protocol.

Cowboy 2.12 requires Erlang/OTP 24.0 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.
