I understand the admin panel states that it cannot be changed once set. I'm in the process of splitting one addon into two and would like to change the ID of a custom user field. It seems it stores the ID it in xf_user_field.field_id and xf_user_field_value.field_id (many times, one for each user with it set) as Hex I naively thought that manually updating these in the database to the new hex value would be a sneaky way round it. It seems to have updated the Custom User Field section in the admin panel, and everywhere else I can see. However, when I try and dump the $user.customFields array into a template, it's still pulling the old ID. I'm stumped, I can't find where it's referencing it from.