I don't know how to search on this topic and not get hundreds of irrelevant hits, so excuse me if this has been answered before.
I just did the upgrade from 2.0.4. I followed the instructions for upgrading in the codex by deleting the old files first, then uploading the new files.
However, when I log in to my admin panel, the version number at the bottom still reads 2.0.4. And I don't see any obvious changes in the admin panel, either. Did I do something wrong?
The only thing I can think of is that I did not delete the wp-admin folder before uploading the new files--I overwrote it. Then realizing what I did, I went back and deleted it, then uploaded the new files.