No known client ever used this. Currently among akkoma-fe, pleroma-fe,
Husky, Mangane and pl-fe only the latter acknowledes the existence of
the in_reply_to_conversation_id paramter in its API definitions,
but even pl-fe does never actually use the parameter anywhere.
Since the API parameter already was converted to DMs internally,
we do not need to make special considerations for already existing
old conversation-addressed posts. Since they share the context they
should also continue to show up in the intended thread anyway.
The pleroma.participants subkey mentioned in docs did already not exist
prior to this commit. Instead the accounts key doesn’t automatically update
and this affects conversations retrieved from the Mastodon API endpoint too
(which may be considered a pre-existing bug).
If desired clients can already avoid unintended participant additions
by using the explicit-addressing feature originally introduced in
https://git.pleroma.social/pleroma/pleroma/-/merge_requests/1239.
With the above-mentioned feature/bug of conversation participants
not updating automatically it can replace almost everything
conversation addressing was able to do. The sole exception being
creating new non-reply posts in the same context.
Neither conversation addressing nor explicit addressing
achieves robust, federated group chats though.
Resolves: https://akkoma.dev/AkkomaGang/akkoma/issues/812
865cfabf88