I’m currently porting a SharePoint Server 2013 site collection to Office 365/SharePoint Online. While uploading master pages, I find the UI version option 4, 15 and 16. This implies that there is a new version on SharePoint in the process of being released to SharePoint Online. It was also confirmed on the European SharePoint Conference that a new Server version was being developed. However, SharePoint Online would get this new version first.
This is the first time I’ve come across UI version 16. Is it what I think it is or something else?