The new version allows the sysop to store the files on the local filesystem, where the previous versions only allowed the files to be stored on Amazon S3.

This server hasn't changed, it's still storing stuff on S3. So this is what we call in software a "regression test" -- has the software regressed as it improves? Can it still do the things it used to do? 

Very often this is a problem, the software "breaks" with new versions. That's why it's important to test for regression.

Atsa spicy meat-aball. ;-)