Breaking: #83153 - Migrated backend_layout.icon to FAL

See forge#83153

Description

The existing database field "icon" for Backend Layouts put into the database, was previously a file upload field, putting all icons under uploads/media. The field is migrated to the File Abstraction Layer (FAL), having proper file relations like all other parts of TYPO3 core.

Impact

When working with the TCA for the backend_layout.icon field, sys_file_reference relations are now expected. When querying the database table directly, icon only contains the number of references of this backend layout.

Affected Installations

Installations with custom backend layout icons and, more specifically extensions dealing with the database table directly.

Migration

An upgrade wizard in the TYPO3 install tool moves all existing icons of backend_layouts from uploads/media to fileadmin/_migrated/backend_layouts/.

For extensions directly working on the database table, the database access needs to be modified.