Limit the time option | WordPress.org

Users can now limit time using below hook

add_filter('gf_awp_calendar_allow_time', 'filter_gf_awp_calendar_allow_time', 10, 2);

function filter_gf_awp_calendar_allow_time($allow_time, $form) {
    // Specify time in 24 hour format.
    $allow_time = array(
        '13:00',
        '01:00', 
        '02:00',
        '16:00',
        '17:00',
        '18:00',
        '19:00',
        '20:00',
    );

    return $allow_time;
}