Further to my comment the other day, I have successfully concluded testing.
Robotype 3.1.2 continues to work, seemingly reliably, under Windows 10 (64bit).
One can run Robotype by clicking on Robotype.exe; right clicking on the Robotype icon in the System tray; and then manually loading the library of ones abbreviations and expansions,
But I remembered that when Robotype is installed it associates its library file suffix, *.rtl, with Robotype.exe.
So I now run Robotype by simply clicking on the name of my saved library file as pinned to the Taskbar. (The name is brought up by right-clicking on the Robotype icon that then appears).
Robotype then runs--with the usual warning about 'chained abbreviations', which I ignore--with the library already loaded.
Stephen