Pressbooks 3.9.4.1

Pressbooks 3.9.4.1 just went live on Pressbooks.com and all of our other production networks. Here’s what changed:

• Feature: The copyright string in the Pressbooks Publisher theme footer can now be customized via the pressbooks_publisher_content_info filter.
• Feature: The text that is displayed when there are no books in a Pressbooks Publisher catalog can now be customized via the pressbooks_publisher_empty_catalog filter.
• Fix: Updated a component of the Diagnostics page to remove a deprecation notice (props to @thomasdumm for the report).
• Fix: Fixed a glitch in the Pressbooks colour scheme.