One last query on 8.1 Upgrade!

I know Windows 8.1 is free but I have few final queries before I take a call on 8.1 upgrade:

1. Will an upgrade from WINDOWS 8 TO WINDOWS 8.1 PREVIEW, means I will have to re install all the apps? Please note I already have a original Windows 8 installed on my box.

2. When I upgrade from 8.1 Preview to 8.1 Final, will my licence that I hold for Windows 8 remain valid?