Trying to restore to 6.0.20648.0 but not successfull

I’m trying to restore emails from old backup which Manifest.xml says following:
6.0.20648.0

I assume the version is that and it seems that the backup is successful as it completes but then the em starts again and it starts like it would be completely new installation and asks the theme and after the configuration there are no new emails.

I would really need to restore the backup to get some old emails.

One thing is that you cannot restore across versions that have different database formats. So for example you cannot restore a version 6 database into a version 7 eM Client.

Well, not directly. Once you have done the restore, (Menu > File > Restore) you then have to import the old database (Menu > File > Import > eM Client 6).