All of our CI systems use gcc 4.8, I believe, but many of us are using gcc 5.x or gcc 6.x on our development systems (I’m running 5.4). I’m not sure if anyone is running on 7.x. As far as I know, the stack itself works fine on all those and we’d consider a failure to work with one of them a high-priority bug.
However, there have been problems with using gcc 5+ with using Anaconda (see DM-10343) and OpenMP (which we do not use ourselves, at least not yet), and in fact that’s been a big blocker for us moving to a newer gcc as our minimum compiler. That’s basically because Anaconda provides binaries that were compiled with a much older gcc. Before doing an Anaconda-based install on gcc 5+ on a big system, it’d be good to read through that issue and understand what might go wrong.