XF 1.1 Requiring order number pattern match at registration: Where to EDIT required pattern?

[HydraulicJack]

In my installation at http://www.multiples.com/orgasmforum/
I installed an order number pattern match requirement (but no table lookup to check against valid numbers) as part of member registration at
http://www.multiples.com/orgasmforum/login/login

The field is:
ORDER NUMBER CONFIRMING PURCHASE of Jack's seminar: Required


It's always worked great but I now need to change the pattern specification and have not been able to locate where this pattern can be changed.

I'd appreciate detailed path to where I'm likely to find the page where I can EDIT the required field pattern, >>>especially without breaking validity of registration of previously registered users.<<<

I also realize that I may have to revert to MANUALLY verifying purchase number against known purchasers, but if that can be avoided I'd sure appreciate knowing how.

THANKS!

 

[Jake Bunce]

Admin CP -> Users -> Custom User Fields

When editing a field there is an option for a regex.

This is also possible with a callback which is in the same area:

http://xenforo.com/community/resources/custom-user-field-callback-validate-value.379/

 

[HydraulicJack]

Thanks very much Jake - as always, thru all the years!!!