relay: add zstd compression in weechat protocol

Option relay.network.compression_level is renamed to relay.network.compression
and is now a percentage between 0 (no compression) to 100 (best compression,
slowest).

Compression is now disabled by default in weechat protocol and must be enabled
via the `handshake` command (option `compression` has been removed from `init`
command).

1 files changed, 25 insertions, 0 deletions

diff --git a/ReleaseNotes.adoc b/ReleaseNotes.adoc
index 2cf8ee423..a731ceefb 100644
--- a/ReleaseNotes.adoc
+++ b/ReleaseNotes.adoc
@@ -17,6 +17,31 @@ https://weechat.org/files/changelog/ChangeLog-devel.html[ChangeLog]
 (file _ChangeLog.adoc_ in sources).
 
 
+[[v3.5]]
+== Version 3.5 (under dev)
+
+[[v3.5_relay_weechat_compression_zstd]]
+=== Compression "zstandard" in relay
+
+Relay of type "weechat" now offers a compression with https://facebook.github.io/zstd/[Zstandard],
+which allows better compression and is much faster than zlib for both compression and decompression.
+
+The new compression type is `zstd`, and the default compression is now `off`
+instead of `zlib`: the compression must now be explicitly given in the
+link:https://weechat.org/doc/relay#command_handshake[handshake] command.
+
+The option `compression` in link:https://weechat.org/doc/relay#command_handshake[init]
+command has been removed, it is now ignored and must be given in the
+link:https://weechat.org/doc/relay#command_handshake[handshake] command
+(it was deprecated since WeeChat 2.9).
+
+The option relay.network.compression_level has been renamed to relay.network.compression
+and is now a percentage between `0` and `100`:
+
+* `0`: disable compression
+* `1`: low compression (fast)
+* `100`: best compression (slow)
+
 [[v3.4]]
 == Version 3.4 (2021-12-18)