Hi, the upcoming Unreal Engine 4.25 introduces a few API breaking changes. Nothing serious, but a few editor classes have been renamed, so the old code will no longer compile as-is. I am monitoring the situation and will publish a UE 4.25 version of GC FSM when the new editor version is officially released. However, for the brave of you that are already experimenting with the new engine and are able to to build the plugin from the sources, I have just pushed a new version, dubbed v1.7.5, of GC FSM. This version includes the necessary UE 4.25 compatibility fixes and no new features or bugfixes.
Enjoy!