Things to do before upgrading to WordPress Mu 2.9.1
Sunday 17 January 2010 at 10:46 am | by Fairweb | 
WordPress development
As Donncha explained it in his post upgrading to WordPress Mu 2.9.1 needs special attention otherwise you’ll probably get errors due to a missing new table in the database.
- Your website must be running under WordPress Mu 2.8.6. Should this not be the case, upgrade manually to 2.8.6.
- Before you upgrade to WordPress Mu 2.9.1, download add-commentmeta.txt and rename it add-commentmeta.php
- Put the add-commentmeta.php file in the /wp-content/mu-plugins directory
- In the administration area, go to Site Admin->Upgrade in order to upgrade all blogs. This will run add-commentmeta.php which will create the missing table for all blogs on your site. Let it run, it may take a while.
- Now upgrade to version 2.9.1 manually or via Tools->Upgrade menu
- Delete the /wp-content/mu-plugins/add-commentmeta.php file
- Repeat the Site Admin->Upgrade operation in order to upgrade all your blogs.
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