Detwoen
I was thinking of doing an upgrade. Bit reluctant as my Win 7 machine is going swimmingly with Sonar Platinum at the moment. But also thinking of the future - I rely a lot on the 8850 and don't want to have to chuck it due to no support.
If the worst happens and you can't find Windows 10 support for the USB port of the 8850, you could always grab yourself a quality USB to MIDI converter connected to the win10 machine and control the 8850 via the 8850's MIDI ports.
That's what I did when I upgraded from the 32bit to the 64bit version of Windows 7. I could not use my Yamaha SW1000XG (no driver support) in win7 64bit. Now I have the SW1000XG in an HP Small Form Factor machine (with win7 32bit) and control it via a Roland USB to MIDI converter connected to the win7 64bit machine.