microsoft.windowscommunicationsapps (Mail, Calendar, People, Messaging)
My original tipster said these apps would also be updated and made available for Windows RT this month. I've tried to find mention of pending updates on my Surface RT and so far cannot. (Wondering if anyone out there with a Windows RT device can see these. Chime in if so.)
Update: It appears this same batch of updates is also coming to Windows RT. Brad Pelletier (@bardo77n) just sent me this screen shot from his Surface RT:
I asked Microsoft again today for comment on when/if these major updates are going to be rolled out. I got a fresh, new "no comment."