safe to upgrade my Mac?

Hi devs, I'm currently running MacOS High Sierra, 10.13.6. Things are fine, but I'd like to upgrade to get Dark Mode and (hopefully) to speed up Mail. (That is, upgrading is nice, but not at all necessary.) If I upgrade, will GHC hate me? That is, will GHC 8.10 continue to work? Will I continue to be able to compile GHC? Will it be as performant? (A few years ago, I had a strange issue on a secondary computer where any binary built by GHC was horribly slow; we never got to the bottom of it.) All advice is welcome. Thanks! Richard