Hi Marc
Thanks for the interest
I have no clue which version it was and can't access admin control panel anymore. The support page deemed the fix as critical issue so I went for upgrade. If I am not mistaken (searched for it in server settings), it says php version is 8.1.27.
btw I just got a response from hosting provider.
Hello,
The error you're encountering indicates an issue with type compatibility in PHP, specifically involving the IPS_DateTime::format method and its compatibility with the parent DateTime::format method. This issue is common when migrating to or using PHP 8.x, as it enforces stricter type declarations.
You or a developer can do a couple of things. For instance, you can modify the IPS_DateTime::format method in the source code to be compatible with the parent method in PHP 8.x.
You can also either update the return type declaration to match the parent method or use the #[\ReturnTypeWillChange] attribute to suppress the notice temporarily.
Though honestly, since the error stems from a third-party PHP application/library (indicated by IPS_ prefix, possibly Invision Power Services), it may be best to contact their support. They might have an updated version of the software that is fully compatible with PHP 8.x. or provide you with more information on how to resolve this issue.
Must admit this is way over my head, I am not a web guy : /