More details: after the upgrade, table "isp_isp_kunde" and table "isp_isp_resellers" have no records. Anyway resellers and customers can login to the panel and I can see resellers and customers in admin CP, but with no data (and no limits for resellers).
If I try to modify customer data, I get no errors but no effect too.
If I try to modify a reseller, I get an error, something like "reseller group cannot be modified" (in italian is "Il gruppo del rivenditore non puň essere identificato")
Please help me!