+++
date = "2025-04-11T07:00:00+01:00"
title = "Gun 2.2"

+++

Gun `2.2.0` has been released!

Gun 2.2 contains many features and fixes, including
an experimental HTTP/3 implementation.

Gun 2.2 is the first release that includes an
experimental support for the HTTP/3 protocol.
Note that unlike Cowboy, Gun 2.2 does not yet
support Websocket over HTTP/3.

Gun 2.2 now sets the appropriate ssl options to
perform wildcard certificate matching, which is
a requirement for HTTP and previously had to be
configured by users.

Gun 2.2 also enables users to send HTTP/2 pings
directly, including over tunnels, enabling use
cases such as measuring the latency with the
server. These pings are separate from the
keepalive functionality.

Gun 2.2 also contains various fixes, the most
significant of which is a better handling of
TLS 1.3 alerts in mTLS scenarios. TLS 1.3 may
perform certificate validation after the handshake
has completed, leading to the alerts often arriving
asynchronously. When an ssl function call returns
`{error, closed}` or equivalent, Gun will now check
whether the closure was a result of a TLS alert,
and in that case propagate the alert as the error
reason to the user. This has also been made to work
over tunnels.

HTTP/2 tunneling has also seen a number of
improvements.

Gun 2.0 requires Erlang/OTP 24.0 or greater and is tested
and supported on Linux, macOS and Windows.

A complete
list of changes can be found in the migration guide:
https://ninenines.eu/docs/en/gun/2.2/guide/migrating_from_2.1/[Migrating from Gun 2.1 to 2.2].

I will now focus on implementing HTTP/3 WebTransport
in Cowboy and Gun.

You can donate to this project via
https://github.com/sponsors/essen[GitHub Sponsors].

As usual, feedback is appreciated, and issues or
questions should be sent via Github tickets. Thanks!