There is a maaaaaajor issue with the wording being used by Microsoft in relating to upgrading from v8.1 PREVIEW to v8.1 RELEASE and it relates to APPS:
APP = stripped out/small/reduced/limited program that typically performs a single task and is (currently) nearly always sourced as a download (i.e. MAIL app)
APPLICATION = full/feature rich/complete/retail program that typically performs multiple related tasks (i.e. Outlook)
I just upgraded a v8.1 PREVIEW to v8.1 RTM and found that the upgrade in fact is a fresh install that migrates your personal data ONLY. BOTH your APPS and APPLICATIONS are wiped out.
The only options during that process was to “KEEP PERSONAL FILES” or “KEEP NOTHING”… this was a clue.
In my case both a full copy of Office Professional and Angry Birds were gonzo.
Microsoft needs to be MUCH more careful with the word APP.
Now the question is what will happen when the Win8.1 “upgrade” is released on Windows Update? My guess is that Windows 8 will nicely UPGRADE to Windows 8.1 and that no APPLICATIONS will be lost.