We always try to ensure WHMCS is compatable with the latest PHP releases but anyone who has tried to run WHMCS on PHP 5.3 in the past few months will be aware that it didn't function properly. This was the unfortunate result of a conflict between Ioncube encoding and this latest version of PHP .

However, we're pleased to advise that today Ioncube has released an updated set of loaders that resolves this issue and so you can now run WHMCS in a PHP 5.3 environment. To do that, you can obtain the updated loaders @ www.ioncube.com/loaders.php

Matt