Update: WordPress 2.9.1 has been officially released and it seems to have addressed the variety of issues that occurred when upgrading, as well as a problem people had with scheduled posts. I gave it a shot on the two sites that choked on 2.9 and it worked seamlessly so I think it’s safe to upgrade at this point.
WordPress released version 2.9 over a week ago but the automatic upgrade has been causing several people problems.
It seems the process will occasionally hang mid-upgrade, often causing database problems with your site.
I tried updating one of my own installations tonight but the automatic upgrade didn’t finish, resulting in every page on my site throwing an error. Thankfully, I had the site content backed up and I needed to move the blog over to Hostgator anyway.
After tweeting my experiences, fellow SEO, Dave Curtis mentioned he had just had similar problems.
I’m willing to chalk one or even two failures up to coincidence but three in a relatively short period of time is enough for a pattern in my mind.
What Can I Do?
The first and most important step is to back up your WordPress installation before attempting an upgrade. That way if anything should go wrong you can reinstall WordPress or your database if it should come down to that.
At this point you can either roll the dice & hope you don’t have to use those backups you just created, or if you want to be 100% safe, you can always upgrade using the old-fashioned manual method.
I’ve heard the problems blamed on everything from plugins, to themes, to different versions of PHP. My failed upgrade seemed to be caused by a slow or unresponsive server but I haven’t been able to verify that. If anyone else has more details on the problem feel free to share them in the comments below.
WordPress 2.9.1 beta has also been released and reportedly fixes some of the bugs that may be causing the upgrade issues but of course, that upgrade has to be done manually as well which can be a bit of a pain for those of us with dozens of installs.
It wouldn’t surprise me at all for 2.9.1 to be officially released shortly and since 2.9 didn’t contain security patches this might be a rare instance where not upgrading is the best course of action.
Update: It appears that at least for my failed upgrade, WordPress recognized the failed upgrade and is allowing me to reinstall the upgrade. I know others haven’t been as lucky but at least some of the failures don’t appear to cause permanent damage.