Events Manager plugin – booking form required fields

I manage to get the answers from this post –> https://wordpress.org/support/topic/change-required-fields-in-registration-form?replies=3

Instead of using ’em_event_validate’

add_filter('em_event_validate','em_validate', 1, 2);

should be using ’em_booking_validate’ in the filter hook

add_filter('em_booking_validate','em_validate', 1, 2);