Stable release will always be in x.xx.xx6!
Public release won't be anytime soon! I expect it around v686-v716
The BETA app has been updated again today (1/17/2015). Now its at version 2.11.628.0 . They seems to be updating it frequently since the past couple of days.
I don't know if anyone has already mentioned this, but WhatsApp chats are now backed up to OneDrive when you do a phone backup. That's why it takes so long to backup WhatsApp. I think it's a brilliant feature. Came in very useful as I had to hard reset my phone yesterday.