Migrating from Ranch 2.1 to Ranch 2.2

Ranch 2.2 is a maintenance release containing a small number of fixes and improvements.

Ranch 2.2 is tested with Erlang/OTP 24.0 onward, although it should be compatible with Erlang/OTP 22.0 and above.

Features added

• DTLS is now supported.
• The certs_keys option from ssl is now accepted and documented.
• The UNIQUE_ID PROXY protocol header extension is now supported.
• The ranch_transport behavior has a new callback format_error/1 which allows finer grained formatting of Ranch's error messages. The callback is currently optional and will become required in Ranch 3.0.

Changed behaviors

• Ranch will now obfuscate certificates, keys and passwords in the error message produced on listen error.
• The exception reason when a connection process has failed its handshake has been changed to {shutdown, {Reason, PeerInfo}} where PeerInfo contains the peer name when available.
• The {packet, raw} socket option is no longer set explicitly, as this is already the default value.

Bugs fixed

• ranch:stop_listener/1 will now return an error instead of throwing an exception when the listener does not exist.
• Fix ranch:recv_proxy_header/2 for the upcoming Erlang/OTP 28.
• Ensure that a user crash while stopping a listener does not prevent a subsequent attempt to stop it.
• Alarm option threshold was mispelled in Ranch 2.1. This has been corrected. The wrong spelling treshold is still accepted and will be removed in Ranch 3.0.