Recently I upgrade my WordPress software from 2.2 to 2.7.1. Here’s my experience:
1. It was painless to download the package from WordPress, unzip it, and then ftp the unzipped files into the web host. Simply following the direction in the WordPress site did the trick.
2. The database upgrade was smooth.
3. After I had finished the processed describe in the WordPress site, I went to the site. Everything looked normal except that the tags were gone. I had been using Jerome’s Keywords plugin to set my tags, and KeyCloud Widgets plugin to display the tag cloud. A little research told me that I needed to use the Tools/Import function to import tags set with Jerome’s Keywords into WordPress’s own tag database (back in the 2.2 days, WordPress did not have native support of tags. That feature was introduced in 2.3).
4. The import was successful and I also edited my theme so the function calls for showing the tags and the tag clouds were updated. However, the tags still did not appear. After more poking around, which included querying the database tables to make sure all the relationships were correct between each tag and each post, I found the solution: I needed to deactivate Jerome’s Keywords. Once I deactivated that plugin, the tags and the tag clouds appeared normally.
In summary, the upgrade from 2.2 to 2.7.1 was relatively painless. The only extra steps were to 1) import tags from Jerome’s Keywords to WordPress, 2) modify the theme so the right function calls are used to display tags and tag clouds, and 3) disable Jerome’s Keywords plugin.