Move to next year when 12 months are added to first payment date (#651)

changelog.txt

@@ -1,5 +1,8 @@
 *** WooCommerce Subscriptions Core Changelog ***
 
+= 7.4.1 - 2024-xx-xx =
+* Fix - Add a year to the next renewal date billing interval is 12 months or more for a synced subscription.
+
 = 7.4.0 - 2024-08-16 =
 * Dev - Introduce new parameter to WC_Subscription::get_last_order() to enable filtering out orders with specific statuses.
 * Update - Schedule subscription-related events with a priority of 1 to allow for earlier execution within the Action Scheduler.

includes/class-wc-subscriptions-synchroniser.php

@@ -686,8 +686,9 @@ public static function calculate_first_payment_date( $product, $type = 'mysql',
 					$month_number = gmdate( 'm', wcs_add_months( $from_timestamp, $interval ) );
 				}
 			}
+
 			// when a certain number of months are added and the first payment date moves to next year
-			if ( $month_number < gmdate( 'm', $from_timestamp ) ) {
+			if ( $month_number < gmdate( 'm', $from_timestamp ) || $interval >= 12 ) {
 				$year       = gmdate( 'Y', $from_timestamp );
 				$year++;
 				$first_payment_timestamp = wcs_strtotime_dark_knight( "{$payment_day} {$month} {$year}", $from_timestamp );