Is it possible to stop Windows 10 to automatically install its upgrades?
Absolutely - otherwise nobody would use it in a large corporate environment. But you need to be on a 'pro/business' edition for that.
The EULA for the home editions states that MS will download the updates automatically but you can still choose when to apply them.
What I am seeing is that, using a single workstation, you can delay downloading and/or installing updates indefinitely by a number of means, including turning off the Windows Update Service.
What you CANNOT do is pick and choose which specific updates to install. You either block all of them, or you are forced to accept all of them. (Yeah, you can let them all be installed, then go and revert some of them and "hide" them after the fact--if they haven't already hosed your computer. Not an acceptable work-around.)
The only way I can see to get control over individual updates is to use the Pro or Enterprise version with a WSUS server. Sure, we all have one of those at home....
Ken Dibble www.stic-cil.org