I just upgraded via the upgrade button in the theme selection (german version of WordPress 2.7.1). Got two problems:
1) My user-defined headerimage was gone. In fact the files header6.jpg, img_1479.jpg and img_1496.jpg were in the directory "images/header". I deleted them with my ftp client and copied my old headerfile. Now everything seems to be fine.
2) In the left sidebar a hint is displayed: "To put some content here, go to Site Admin -> Appearance/Presentation -> Widgets -> Select "Left Sidebar" -> Click "Show" -> Click on "Add" on one of the widgets on the left side -> Click "Save changes" -> Done " I'm waiting for responses of users what that should be good for... Here I haven't found a solution yet.
CAN YOU PLEASE HELP ME?