If you are planning to upgrade wordpress to latest release, do the following
- Read Worpdress Support forums to see any upgrade problems
- Backup Entire Database
- Check for Minimum Requirements ( MySQL, PHP)
- Check if all installed plugins supports the latest version of wordpress.
- Deactivate all the plugins
- Know how to revert to previous wordpress version, if upgrade were to fail.
- Test the upgrade in local wordpress installation ( if downtime of site might be major issue)
- Perform WordPress Upgrade
- Upgrade WordPress Database if required
- Check if Site is up and running.
- Click on few links to to check if URL structure is maintained.
- Activate the supported plugins one at a time.
WordPress 2.8.6 to 2.9 upgrade created couple of problems. It was because
- Some of the plug-in’s didn’t support 2.9
- db_version in Table WP_Options had incorrect value.
After I fixed the db_verison, site was up and running, but all the url was broken. It was due to unsupported some plug-in in 2.9