Billing module fails to load Invoice tab

Probably your old Billing Module version is not compatible with PHP 7.4.

As a sidenote, ISPConfig itself does not support PHP 7.4 on Ubuntu 16.04. You can use PHP 7.4 as an additional PHP version, but never exchange the system PHP of a distribution as this can cause all kinds of problems and malfunctions in installed software that uses PHP. The main PHP of the system gets updated when you do a dist upgrade of the server, e.g. by upgrading to Ubuntu 18.04.

 

The Billing module you use has been released in 2017, so it's nearly 3 years old, you can keep using that old version but have to switch back the system PHP as I mentioned in my post above. The current version is 2.0.9 and has been released in January 2020 and has been tested with all PHP versions that ISPConfig supports, the highest PHP version supported by ISPConfig at the moment is PHP 7.3, support for PHP 7.4 will be added soon when we add support for Ubuntu 20.04.

 

The billing module license includes free updates for 12 months after purchase, your version is nearly 3 years old, so the 2.0.9 update is not covered in your license anymore. If you want to update, then you can purchase a new license using this link:

https://secure.2checkout.com/order/checkout.php?PRODS=14290285&QTY=1&CART=1&CARD=1

I'll send you an update rebate code by email.

 

just run:

php update.php

 

There is no list for that available at the moment. Basically it are many smaller changes to add support for new ISPConfig, PHP, and MySQL versions.