Upgrading to Wordpress 2.1
Just upgraded Chocolate Gourmand Blog to Wordpress 2.1 I recently upgraded it to 2.07 for a security fix and noted they said 2.1 was coming at end of month. Just like installing Wordpress, upgrading is a snap. Here's what I would recommend doing for a smooth upgrade with minimal or no downtime:
1. Backup your existing wordpress installation files to a secure location. The easiest way to do this is to copy it to your local machine.
2. Backup your database. If you don't already have it installed, I recommend using a wordpress plugin to do this called--appropriately enough--Wordpress Data Backup.
3. Speaking of plugins, take a look at your plugins page and note which ones are installed but not enabled. I decided to remove the ones I don't use (tried them out and didn't like) so future upgrades would be simpler as I forget this step (and to copy plugins to new install) and had to figure out which recent comments plugin was the one I actually used.
4. Download and unpack the wordpress installation files from the WordPress download page.
5. Copy your wp-config.php file and your specific themes folder along with your special plugins (don't overwrite akismet plugin in new install--it is an upgrade, too) from your current install into the new wordpress folder. Upload the new wordpress folder to your site as a side folder (e.g. if your blog is under /blog/ then upload new files to /blog_new/). If you have any other customizations to files outside of the themes folder, merge those changes into the new wordpress files. I did notice that they did away with the template-functions-general.php and all the template* functions for a general-template.php page.
6. Open up your WordPress admin home page and log in if you haven't already done so. Rename your existing blog folder to something like blog_backup and now then you can rename the new folder you uploaded to the normal blog folder name (e.g. blog_new to blog). Reload the admin page, click upgrade, click upgrade again, watch the progress meter and you are done.
7. Double check that your plugins are all still activated and then check out your site. Hopefully it all worked out. Downtime should have been limited to less than a minute.