vBulletin allowed the same upgrade to be purchased multiple times and would save it with the same ID against a user.
This obviously creates an issue in XenForo which requires the ID's to be unique.
This obviously creates an issue in XenForo which requires the ID's to be unique.
Code:
[XF\Db\DuplicateKeyException]
MySQL query error [1062]: Duplicate entry '13449681-3' for key 'user_id_upgrade_id'