We've never synchronized chats from the server after the first login AFAIR. We just display/open chats for incoming new messages, but that's all. Only MIX channels could be opened if any was added to the roster.

OK, then this could be treated in two ways:

1. IMHO we should try to synchronise chats upon first login (maybe part of the improved onboarding?)
2. there wasn't any MIX chat opened even though I should have at least two (tigase/int)

I enabled "sync bookmarks" option and this resulted in groupchats appearing, but still - no MIX channels (possibly recent issue with MIX joining/leaving happening at the same time?). What's more - IMHO the sync option should be enabled by default (wasn't there a mockup by Holger with a screen with multiple toggles end "preferred" options enabled by default?)

1. IMHO we should try to synchronise chats upon first login (maybe part of the improved onboarding?)

There are no "chats" on the server side so how and what should we synchronize?

there wasn't any MIX chat opened even though I should have at least two (tigase/int)

But those are joined already. Most likely a bug in the old version of TigaseSwift used by SiskinIM.

I enabled "sync bookmarks" option and this resulted in groupchats appearing, but still - no MIX channels (possibly recent issue with MIX joining/leaving happening at the same time?).

MIX channels are not part of the bookmarks. They are stored in the roster only.

What's more - IMHO the sync option should be enabled by default (wasn't there a mockup by Holger with a screen with multiple toggles end "preferred" options enabled by default?)

There was no new version for quite a while so no changes to the settings were applied.

There are no "chats" on the server side so how and what should we synchronize?

Assuming there is MAM (and we do have it):

1. querying general archive for the messages in the last week
2. querying last X (10? 20?) messages for all roster items.

I'm aware that, especially the second option, would cause some load on the server, but having it would improve greatly first experience with the application.

But those are joined already. Most likely a bug in the old version of TigaseSwift used by SiskinIM.

OK, just mentioning it here. If it's a "known issue" and was already fixed that's good :-)

MIX channels are not part of the bookmarks. They are stored in the roster only.

You are right and I knew it, hence mentioning the issue about joining/leaving which caused removal from roster.

OK, so you want to sync messages from the last week automatically and not chats, correct? or you want to open chats for them as well?

I would imagine that syncing those messages would automatically create corresponding chat entries? And would give a user some "starting point"

Well, we do not do that for messages synced by MAM during catch-up, but I think we could make an exception for "initial sync" or ie. open last 5-10 chats.