YunoHost 4.2 testing

Hi,
I have an issue when trying to restore a backup (after a fail upgrade of synapse). I write a post here.
Since the restore option told me :

This backup archive can not be restored because it comes from a too-old YunoHost version. 

it might be an issue with 4.2.2. (This is why I link it there.)
I have no idea how to solve this :frowning_face: