Unfortunately, Micro-Checker is a pretty old application and finding data about it online proves to be quite challenging. Furthermore, I downloaded the version available on SI and I didn't see any limitations, which means that you shouldn't have any problems using the tool "as is".
However, for additional licensing information, I recommend contacting the application's developers directly using these email addresses: peter.shipley@bcs.org.uk and C.van-Oosterhout@hull.ac.uk or getting in contact with The Hull University using the following phone number: +44 (0)1482 346311.
