Issues on Ubuntu 22

Hi
I've just installed v3.4.1 on Ubuntu 22. Working somehow OK on PHP 8.0.25. On PHP8.1 i get an error as below
PHP Fatal error: Uncaught mysqli_sql_exception: Unknown column 'utf8_decode' in 'field list' in /var/www/html/nagiosql/functions/MysqliDbClass.php:111\nStack trace:\n#0 /var/www/html/nagiosql/functions/MysqliDbClass.php(111): mysqli_query()\n#1 /var/www/html/nagiosql/functions/NagConfigClass.php(754): functions\\MysqliDbClass->getFieldData()\n#2 /var/www/html/nagiosql/functions/NagConfigClass.php(1197): functions\\NagConfigClass->getConfigData()\n#3 /var/www/html/nagiosql/functions/NagConfigClass.php(1105): functions\\NagConfigClass->writeConfTemplate()\n#4 /var/www/html/nagiosql/functions/prepend_content.php(547): functions\\NagConfigClass->createConfigSingle()\n#5 /var/www/html/nagiosql/admin/services.php(39): require('...')\n#6 {main}\n thrown in /var/www/html/nagiosql/functions/MysqliDbClass.php on line 111, referer: https://nagiosql-ix.rim.local/admin/services.php

and also PHP Deprecated: addslashes(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/html/nagiosql/functions/prepend_content.php on line 166, referer: https://nagiosql-ix.rim.local/admin/services.php but this one on PHP 8.0 as well.

Any help would be appreciated.

Thanks