Upgrading from Pressbooks 3.x to Pressbooks 4.x


Pressbooks 4.0 (and our other open source plugins) rely on the Human Made autoloader, which is bundled with the Pressbooks plugin. Before you can use Pressbooks 4.0, you will need to copy the file from:




This will make it available to Pressbooks and any other plugins that require it. You may need to create the wp-content/mu-plugins/ directory if it doesn’t yet exist.


Pressbooks >= 4.0 requires that themes previously bundled with Pressbooks 3.x be installed separately. For installation instructions, consult the README file of the theme(s) you need to install below. (NOTE: theme folders must not have version numbers on the end. GOOD: pressbooks-publisher. BAD: pressbooks-publisher-3.1.0. If you are installing manually, make sure that you rename the folders appropriately.)

Two themes are required for all Pressbooks installations:

The remaining themes are recommended but optional, and they are required if you used them on Pressbooks 3.x: