The spar will work the same on Windows 10 as the supported OS's since it only applies to the printer.
The printer doesn't have Windows 10 support (So there are no native drivers or testing) so it doesn't show up in the supported OS's
But the GPD supports Windows 10, and the GPD supports the printer, so that is listed under Windows 10 drivers.
Nothing print related has really changed from Windows 8.1 though, minor changes were made to WSD compatability, but if you stay with a V3 driver using a Standard TCP/IP port all should be well. The v4 Class driver is provided by MS.