I found the following on Brandon Sanderson's Blog:

 

 

Tor is readying a press release about the release date of the book. I suspect you'll see that next week as well

5€ says it's the "book is so big we'l chop it in two/more and release the first part at date X" -announcement.

I doubt you'll get any takers here without offering significant odds.

I hope we get the companion volumes. Or the WoT Encyclopaedia. I'm hoping that's part of the announcement as well.

 

 

I hope that they would decide to release all of RJ notes, I doubts that it would ever happen, but if it would, it would be amazing.