If we release mobile and desktop at the same time:
New server, old mobile:
Old server, new mobile: No new threading option (server does not support it)
New Server, new mobile: Show new threading option (user can choose in account settings to disable or enable folded threads)
Old server, old mobile: No new threading option (server or mobile app does not support it)
If server releases before mobile:
can we do something interm on mobile? If using wew server, but old old mobile, then revert to above ^