E.g. the event is on the 03 of September 2023 and the attendee must be 18 on the event date, when signing up for this event he isn’t 18 yet, but on the event date, this person is. How can we manage to check the age based on the age validation hook?
There is just one line you need to change to do what you want. In the line that has new DateTime(), you can just insert the date you want. So in your case, you would change the code snippet to this: