WordPress 3.3 just landed on wordpress.org for release a bit ago. Everyone will be getting that 'Upgrade Now' notification in their dashboard shortly. Here's what you need to know:
1. We always advise you running a test update on a development install BEFORE running it on a live site. Additionally, you should always make a complete backup of your files and your database before attempting a WordPress upgrade. (Trust us, we've skipped this step in the past and it wasn't pretty)
2. We are working hard to make sure all our plugins/themes are ready to go for you (most of the time within 24 hours). Several of our products have already been updated. If you're unsure about a particular product, then just ask!
3. BuddyPress - compatibility with the new userbar is being worked into 1.5.2. If you're using BuddyPress it's best to wait for this release (shouldn't be too long) *Edit* Available now!
4. How should I upgrade? Well, you already made a backup and tested things out, right? Good. First of all check your plugins/themes and see if they have updates available that say 'WordPress 3.3 compatibility' in the changelog. This, or really any plugin/theme update should be done first. Once you're up to date you can go ahead with the WordPress Upgrade.
4a. For many folks, updating WordPress manually produces better results. To do this, simply download the latest version from WordPress.org and upload it to your server via FTP. Remember upload everything except your wp-contents folder and wp-config.php so that you don't lose your plugins/themes/uploads/etc.
4b. Go to your WordPress admin, for multisite you'll see a notification about upgrading your network. This will bring all your sub-sites up to the latest version.
4c. Do some testing! Check and make sure that everything is in good shape. If something appears wrong report it here in the forums or on the forums on wordpress.org
5. There's no rush. Yes, the latest and greatest is super cool - and we all feel the need to upgrade immediately. However, in daily practice waiting for the .1 or .2 release (ie WordPress 3.3.2) is often a good method as new bugs are bound to be found and fixed up from the new 3.3 release.
Lots of new stuff to enjoy in this version. What are you most exited about? What do you think of the new interface?