I'm a software developer who lives in Cambridge, Massachusetts and works at Microsoft, working on Visual Studio and Team Foundation Server.
Recently Jesse Houwing, one of the Team Foundation Server MVPs, wrote a helpful blog post outlining client/server compatibility in TFS. One of the interesting points in this list is that our cross-platform TFS tooling, Team Explorer Everywhere, is compatible with a wide range of TFS servers, going all the way back to the first version of Team Foundation Server. Having worked with this team for many years now, this isn't surprising to me; this is a team that takes compatibility very seriously.
You can see this passion in the requirements sheet - it reads more like a who's-who of modern operating systems than a typical supported platform list from Microsoft (and, frankly, some of these platforms are starting to feel... less than modern). But one thing most people don't see is the actual infrastructure that we use to support all these platforms. The machine room in the TFS North Carolina office is home to the TEE build and test lab, much of the hardware becoming increasingly rare anywhere but certainly these machines are unique at Microsoft. Only a handful of people are familiar with this lab, but this is one of my favorite places in the Raleigh-Durham office, so I was certain to snap a few pictures the last time I was in town.