In the release notes it states:

That does not appear to be true. If I create a new test request and edit it - it updates the 'Last Updated Time'. If I add a note to the request it updates the 'Last updated time'. If I reply it updates, which is what it says it will do. Problem is any other update anything at all causes that value to update. - not 'only' a reply.

I would like to be able to filter on when the technicians last reply to a request but I don't see a way to do that. But the above is not true and is easily replicated/tested.