I upgraded a Joomla site from 1.6.5 to 2.5 successfully.
However, the webhost company found at least one file that seems to belong to the old version (libraries/joomla/version.php). 

The file contains : 

```
 public $RELEASE    = '1.6';

```

So, I removed that file.

My question : **How can I verify that there are no other old files left after the update?** That webhost company is super picky and wants to make sure that there is absolutely no trace left of the old Joomla version (apparently this would cause a major a security treat, bla bla bla...). 

Thanks !