When a new WordPress version comes out I always like to wait 3-4 weeks to allow for sufficient burn in with the assumption that any major bugs will be corrected by the time I upgrade. One of my cardinal rules of upgrades is to have a working backup and to make sure I have sufficient time to troubleshoot and quickly correct if something goes wrong. I delayed upgrading to the latest version of WordPress longer than my typical 3-4 week burn in time because it required me to be operating at a higher level of PHP configuration vs. what I was currently operating at and I thought it would be a bigger deal to change.
Since this site is dedicated to security I did not want to get more than one version behind the WordPress current version level (got to keep practicing what I preach here). I logged into my hosting account and was pleasantly surprised to learn that upgrading my PHP version was a point and click painless upgrade.
To upgrade my PHP I performed the following:
Logged into my hosting account
Go to cpanel
Changed from PHP 4 to PHP 5 and clicked Update
I then checked back in my WordPress site and was now able to upgrade to WordPress version 3.2.1 when previously a not compatible with your version of PHP was previously displayed. I was then easily able to auto update to the latest version like all previous updates.