Clarify the support for Sliding Sync in Synapse and its compatibility with the syncv3 proxy

[4nd3r]

Since Synapse v1.112 several Sliding Sync related changes have been merged.

The only comment I found regarding the Sliding Sync in Synapse versus the syncv3 proxy was here.

It now appears (#17571) that this feature is becoming switchable and Synapse will publish this capability as well.

Could you please clarify, in documentation and/or release notes, how this affects installations that use the syncv3 proxy?

Should I disable the proxy, remove related bit in .well-known/matrix/client and enable Sliding Sync directly in Synapse now?

How this impacts Element-X clients/users?

[erikjohnston]

Hi @4nd3r, we're currently in the middle of adding sliding sync support to Synapse, but it's not yet ready for people to start switching over (though hopefully will be soon). Once we get to the stage where people can start using the native implementation we'll shout about it and provide docs.