Sounds like it's the same as in HS: https://twitter.com/realmrpippy/status/1003721717921902595/photo/1Fusion Drives are supported.
Mojave will be the last release to support 32-bit at all. They didn’t say which “compromises” there are in Mojave.
I suppose some APIs are removed perhaps. There doesn’t appear to be anything critical so far.Sounds like it's the same as in HS: https://twitter.com/realmrpippy/status/1003721717921902595/photo/1