Source:
https://www.reddit.com/r/redditsync/comments/14hb7h3/comment/jpcby48/
Correction: the pop up for Lemmy should start to appear sometime this weekend
Also apparently confirmed in discord that kbin support will be coming:
As a heavy Sync Pro user for something like a decade, with a lot of respect for ljdawson and the work he put in - the announcement that heβs working on a new version for Lemmy was what pushed me to move away from Reddit and give this a shot. So excited for the new project! Hopefully other users feel the same way I did.