preserve start date when PMPro WooCommerce subscriptions go into "on hold" status

my_pmprowoo_on_hold_keep_startdate.php

function my_pmprowoo_active_preserve_startdate( $level_id, $user_id )
{
	global $wpdb;
	if( $level_id != 0 && did_action( "woocommerce_subscription_status_active" ) )
	{
		$startdate = get_user_meta( $user_id, "pmprowoo_startdate_$level_id", true );
		if( !empty($startdate) )
		{
			$wpdb->query( $wpdb->prepare( "UPDATE $wpdb->pmpro_memberships_users SET startdate = %s WHERE user_id = %d AND status = 'active'", $startdate, $user_id ) );
		}
	}
}
add_action( "pmpro_after_change_membership_level", "my_pmprowoo_active_preserve_startdate", 10, 2 );

function my_pmprowoo_on_hold_save_startdate( $level_id, $user_id )
{
	global $wpdb;
	$old_level = pmpro_getMembershipLevelForUser($user_id);
	if ( $level_id == 0 && did_action( "woocommerce_subscription_status_on-hold" ) && empty(get_user_meta( $user_id, "pmprowoo_startdate_$old_level->id", true )) )
	{
		update_user_meta( $user_id, "pmprowoo_startdate_$old_level->id", $old_level->startdate );
	}
}
add_action( "pmpro_before_change_membership_level", "my_pmprowoo_on_hold_save_startdate", 10, 2 );