PHP error in Mysql.php

I have Matomo 3.13.1-rc1, and PHP 7.4.1, 10.3.18-MariaDB-0+deb10u1.
when I enter the monitored website, I receive an error in the log

PHP Notice: Trying to access array offset on value of type int in /var/www/xxxx/matomo/core/Tracker/Db/Pdo/Mysql.php on line 48

My Mysql.php

`} elseif (!empty($dbInfo['port']) && $dbInfo['port'][0] == '/') {`

please help

Hi there,

We fixed this bug in Fixes warning for newer PHP versions by sgiehl · Pull Request #15376 · matomo-org/matomo · GitHub
can you try apply the patch manually and confirm this works for you?

thank you, works fine