11
Try the
version 2.0.2The instruction for upgrade from 1.3.x are
here. Just make sure that you make backup of all your files and the database before you do anything.
Once you convert successfully to 2.0.2, make a backup and then you can try to do a direct conversion to 2.5.1, but if this doesn't work, try to update to
XOOPS 2.0.13.2, and then to 2.5.1
Keep us posted if this worked, so we can advise people in the future...