I found the update for Windows 10 automatically checked in my updates today. Had I had automatic updating turned on, it would have upgraded to Windows 10 without my permission. It seems it's no longer opt-in, but opt-out.
The only option for anyone who doesn't want to upgrade is to turn automatic updating off, keep it turned off forever, and manually verify every update you receive, making certain the update to Windows 10 is unchecked every single time. Microsoft only going to become more aggressive and more deceptive about this in the future. They can no longer be trusted with their own product. Windows Update has become no better than the adware-infested installers that CNet or Sourceforge wrap applications with.
I'll probably upgrade sometime before then, I just happen to be quite comfortable with what I have right now. Before then, I plan on just blocking the upgrade. I have another Windows laptop I'm strongly considering installing Ubuntu on to use for everything except Adobe software and Visual Studio.
The only option for anyone who doesn't want to upgrade is to turn automatic updating off, keep it turned off forever, and manually verify every update you receive, making certain the update to Windows 10 is unchecked every single time. Microsoft only going to become more aggressive and more deceptive about this in the future. They can no longer be trusted with their own product. Windows Update has become no better than the adware-infested installers that CNet or Sourceforge wrap applications with.