Upon start up it will inform you about old kde 1.x configuration files and recommends to remove them. Which is fine, but what does it do!? (1) It removes all 2.1 config file and all your configurations are gone (in particular all my ppp settings were gone and I had no backup, thanks a bunch for that!) (2) Not only this, IT WILL EVEN REMOVE FILES WHICH ARE TOTALLY UNRELATED TO KDE!!!!!!!!!!! In particular, it will remove ALL files in ~/Desktop. Why doesn't it AT LEAST MOVE THE FILES TO THE TRASH!!!
See the reply on testers-list for details - this happens only when updating from a non-clean 2.x install to the new packages. Not very nice, but inevitable. I'll move the files to the trash rather than killing them completely in the next version.
Fixed in 2.2-0.alpha2.2