Thank you dbs, I have upgraded to 2.12.2, now I'm having a few problems:
1) I'm not being able to upgrade to the latest FolderGallery version (or any other version), I get the following message:
 It is not possible to upgrade or install from a WebsiteBaker Versions before 2.12.1
2) The backend is horribly slow. I get this problem on every medium / big site which has kept me away from versions > 2.10, but I forgot about it and upgraded this one. Fortunately the frontend doesn't seem to be slow as has been the case with bigger sites.