PHP Deprecated (with php 8.1) in letsencrypt.inc.php

Ubuntu 22.04/PHP 8.1.24 (cli)/ISPConfig 3.2.11

If certbot is used then server.php shows (php8.1)

PHP Deprecated:  explode(): Passing null to parameter #2 ($string) of type string is deprecated in /usr/local/ispconfig/server/lib/classes/letsencrypt.inc.php on line 47
PHP Deprecated:  explode(): Passing null to parameter #2 ($string) of type string is deprecated in /usr/local/ispconfig/server/lib/classes/letsencrypt.inc.php on line 471