WooCommerce validate coupon by expiry date and time

This can be made in a more simple and effective way. You can use the following instead:

add_filter( 'woocommerce_coupon_validate_expiry_date', 'filter_coupon_validate_expiry_date', 10, 3 );function validate_coupon( $valid, $coupon, $discount ) {    $expiry_date     = $coupon->get_date_expires();    $expiry_time     = $coupon->get_meta('expiry_time'); // Coupon custom field     if ( $expiry_date && ! empty($expiry_time) ) {        $timezone        = $coupon->get_date_expires()->getTimezone(); // get timezone        $expiry_datetime = new WC_DateTime( $expiry_date->date('Y-m-d') . ' ' . $expiry_time );        $now_datetime    = new WC_DateTime();            $expiry_datetime->setTimezone( $timezone ); // set time zone        $now_datetime->setTimezone( $timezone ); // set time zone                 $valid = $now_datetime->getTimestamp() > $expiry_datetime->getTimestamp();    }    return $valid;   }

Code goes in functions.php file of the active child theme (or active theme). Tested and works.

For plugins that uses a Class with methods and functions, you will replace:

add_filter( 'woocommerce_coupon_validate_expiry_date', 'filter_coupon_validate_expiry_date', 10, 3 );

with:

add_filter( 'woocommerce_coupon_validate_expiry_date', array($this, 'filter_coupon_validate_expiry_date'), 10, 3 );