This add-on can help you to restore vertex groups when opening or appending meshes made with Blender 3.0 in Blender 2.9x versions.
When meshes created in Blender 3.0 are opened in or appended to Blender 2.9x, their Vertex Groups could be lost. This is due to backward compatibility issues.
The Restore Vertex Groups add-on can partially restore vertex groups for such objects.
The mesh saved in Blender 3.0 and appended to Blender 2.93 looks like this:
After processing by the add-on, the vertex groups are restored with the base names:
The add-on restores only the vertex groups themselves, but, unfortunately, does not restore their names. Therefore, the restored vertex groups are named in a basic way: Group, Group.001, Group.002 …. etc. You need to manually rename them.
Add-on web page
Current add-on version: