Error in new account registration

Hi,

I have upgraded osTicket to 1.15 and my PHP version to 7.2.
When I tried to create new account and click register I got error 500.

When I see PHP error log I got
PHP Fatal error: Uncaught Error: Call to undefined method UserAccount::checkPassword().

I hope someone can help me.

Thank you so much

First thing I would try is to upgrade to current 1.15.1.

You also might want to post the rest of the error, you seem to be missing most of it.