public function process_popup( $popup_id = 0 ) {

		$popup = pum_get_popup( $popup_id );

		/**
		 * If the popup is already updated, return early.
		 */
		if ( $popup->data_version < 3 ) {

			/**
			 * Processes the popups data through a migration routine.
			 *
			 * $popup is passed by reference.
			 */
			pum_popup_migration_2( $popup );

			/**
			 * Update the popups data version.
			 */
			$popup->update_meta( 'data_version', 3 );
		}
	}