A temporary solution for this problem, can be to check in the database on table oc_t_preference and find the table in wich is save the osclass version.
But beware, and make a database backup before doing this.
I encountered this problem once myself, and in that table was not the correct version, even after i did update to the latest version there remained the old version.
After i modified that table and i include the new version the message disappears.