[jmau111]

Users have reported various performance issues. It does not make 11 worse than 10. It's more secure to keep windows 10 if your hardware is too old.

[jmmv]

I'm asking about security, not performance or anything else. How does 11 make old hardware less secure than 10, assuming it's only new features that cannot work?

[jmau111]

Performance is important, as you don't want to have a dysfunctional system, but, typically, you have to disable important security mechanisms to force the install.

You lose on both sides.

[neogodless]

Do you lose any security benefits (of Windows 10) by updating your system to Windows 11, or just "new" Windows 11 security mechanisms?

[AstralStorm]

The same security mechanisms are available in new Windows 10 builds, but it does not enable them automatically because of said ancient machines.

In particular certain security issue mitigations are terrible performance on older CPUs (think easily up to 20% performance loss). If your machine is ancient enough, it won't even get Core Security.