Introducing the Classic theme
As part of the constant evolution of Moodle, Moodle HQ removed the Clean and More themes from their codebase starting in Moodle 3.7. This change allowed Moodle HQ to focus on the Boost theme and new themes with more modern technology and user experience.
The Open LMS team stated that we would support the Clean and More themes until they weren't part of Moodle HQ's codebase. We removed the Clean and More themes from our support starting in the Open LMS 3.7 release.
Moodle HQ created a new theme, Classic, that mimics the Clean theme. This theme offers more modern technology and an updated user experience.