Come together with the global Drupal community in Rotterdam, 28 Sept – 1 Oct 2026. Sessions, contribution, connection, and Early Bird savings until 8 June.The theme named Classy is deprecated as of Drupal 9.5.0, and the 2.x branch of Bootstrap5 lists this as a base theme, which triggers a warning about a deprecated theme being enabled when you visit the "Status report" for the site,
This problem is partly solved for the 3.x branch (which is compatible with Drupal ^9.4 and ^10), please see #3314491: Split D9 and D10 branches as classy removal breaks functionality for background.
Setting up a new website with the 3.x branch of Bootstrap5 does not produce this warning, but installing Drupal 9.5.0 on a site that is currently using the 2.x branch does, and switching to the 3.x branch does not make the warning go away 😞. To learn how to fix this for now (until it has been fixed in core), please see this bug report for core: #3328016: Deprecated core themes cannot be disabled on the "Appearance" tab because they are hidden.
Since the recommended release for Drupal 9, version 2.0.5 has this issue, the release a stable release of the 3.x branch shall be appreciated-
Comments
Comment #2
gisleLinked to bug report for the core theme system in issue summary.
Comment #3
gisleUpdated issue summary with recommendations about what to do if you're using Bootstrap5 version 2.0.5 and experience this.
I am also requesting a release of a stable version of the 3.x branch, but I understand there are issues, re: #3324046: Drupal 10 release.
Comment #4
mustanggb commentedJust encountered this as well, probably the best option is to work on getting a stable 3.x release.
Comment #5
vladimirausSee #3331443: Add required SCSS/CSS fixes after removal of Classy and Stable and add separate tasks ti fix individual SCSS/CSS issues.
The plan is to keep 2.0.x with Classy and 3.0.x without Classy.
I'll update the description.