I like to take risk. So, instead of five steps to upgrade my WordPress, I did it by dumping the files I downloaded from WordPress after I did a backup and deactivate plugins.
And I had done it for my Christian-journey without a hitch.
Except for the Askimet plugin. It is bundled into WP 2.1 and at first, I had broken links when I activate the Askimet plugin. Did another dumping and ok, it works now. Therefore, it is very important to deactivate all your plugins and activate it one by one. Especially if you have lots and lots of plugins like my personal blogs. This way, you know which plugin is not compatible.
You can read what’s new with WP2.1 but what I had gleaned through seems good. Auto-save, no more losing my lengthy posts due to the horrible internet connection. And easier management of comments. The rest? They are Greeks to me.