I've said this on another thread, m personal machine and the machines of others I'm given to take a look at as well as the people I know here and beyond, all are on 2004. I'd suggest you backup any and/or all data that may be critical to you and then proceed with the update(reinstall). After backing up data, I'd advise on making sure you're on the latest BIOS update prior to the update.
The matter is that Windows 10 requires you to be up to date to ensure stability.