RootsMagic 8 will not have a Linux version on release. It's on the enhancement request list but I do not know if or when we will see a Linux version. The big issue with Linux support are the multiple flavors of Linux, we cannot write to them all.
I'm really not interested in running Linux on the desktop. But my experience with Linux suggests that from the application side such as RM, the multiple flavors of Linux are probably not a big deal. Server side software is another thing entirely.
I do presently have a Linux server in my house - 16 processor cores, 64GB memory - but I have never run RM on it and I'm sure I never will. What I run on it are scientific research type C++ programs that I write and which require enormous amounts of resources. I develop on Windows with Visual Studio, and I run the resultant EXE files under Linux under Wine. For what I'm doing, it works great but I'll stick with my Windows desktop.