PHP 7.2 upgrade

May I ask kindly for PHP 7.3 Support.
Currently I’m running on PHP v7.2.13 but as all other Webapps are running on PHP 7.3 this would be awesome!
If I can help with logs let me know

#EDIT: I just post the Error after switching to PHP 7.3 here

#### A PHP Error was encountered

Severity: 8192

Message: strpos(): Non-string needles will be interpreted as strings in the future. Use an explicit chr() call to preserve the current behavior

Filename: MX/Router.php

Line Number: 224

Backtrace:

File: /var/www/vhosts/domain.tld/httpdocs/rechnung/application/third_party/MX/Router.php
Line: 224
Function: strpos

File: /var/www/vhosts/domain.tld/httpdocs/rechnung/application/third_party/MX/Router.php
Line: 71
Function: set_class

File: /var/www/vhosts/domain.tld/httpdocs/rechnung/index.php
Line: 325
Function: require_once