Following the good experience we had with WordPress 3.o, it looks like it’s time to start thinking about upgrading.
But, with great power comes great responsibility. WordPress 3.0 is a major change from previous versions. True, it uses the same tables, but a lot of the API has changed. This can cause existing plugins and your theme to go wild.
I’d like to tell about what we did to make sure everything runs smooth after the migration.
Migrating to WordPress 3.0
First, you should do a complete backup. I just zipped everything from the wordpress directory (including WordPress core itself). Then, created a database backup.
You can make selective file backup as well, but a few more MB of backup are not going to hurt anyone and its way easier to use, should anything go wrong.
2. Create a test site
Going from WordPress 2.9.0 to 2.9.2 is pretty safe, but the jump to WordPress 3.0 calls for a staging site.
Create a new test site and unzip the files backup you made before.
Next, you need to copy the database.
For this, you can’t just copy. You need to edit the SQL dump. Open any text editor and do a global replace for the site’s domain. Supposing your live site is www.justgreat.com and your staging site is dev.justgreat.com, replace all:
www.justgreat.com -> dev.justgreat.com
This SQL dump replacement means that everything in the staging site goes to the correct URL. Now, you can apply the database.
3. Check that your test site is good
So far, we haven’t done much. We just have a full copy of our live site where we can test on. Check that it works correctly and we’ll move on.
4. Update to WordPress 3.0
And, we’re ready. Now, get the latest WordPress nightly build. Unzip it over your current version in the staging site.
Log in to the WordPress Admin. The first thing you’ll see if that WordPress suggests to update the database.
And, you’re done. Now, you’re seeing how your site looks like in WordPress 3.0.
Is it working?