The JLex Module has this PHP error/warning:

Passing null to parameter #1 ($string) of type string is deprecated in /modules/mod_jlexcomment/mod_jlexcomment.php on line 38

The fix is simply changing this:

$moduleclass_sfx = htmlspecialchars($params->get('moduleclass_sfx'));




To this:
$moduleclass_sfx = htmlspecialchars($params->get('moduleclass_sfx', ''));

which passes a default value in case of it being null.