Beta 1 is planned for three weeks from now, and is a fairly reasonable target. There's a lot to get done for release, though, both for Elkarte and in terms of getting the importer to something I would be willing to put E through. Shutting Elliquiy down for days is not an option IMO.
No rendering changes in terms of structure. Some major style alterations, of course, though that's not really going to impact BBCode much. There is more to be discussed about plans after the upgrade, but I would rather show than tell there.