You can disable Secure Boot by restarting your PC and opening the Unified Extensible Firmware Interface (UEFI).

While some of these features are possible on devices without a TPM, they’re more secure if you have one. Requiring the TPM on all Windows 11 devices lets Microsoft set a security floor.

I think the article told me how to prevent my fleet of PCs updating to windows 11: turn off secure boot. I wonder if that also will allow me to boot old media on PCs that have had this patch fully ...

Secure Boot is a feature of your computer's UEFI that only allows approved operating systems to boot up.

Windows 11/10 provides the necessary Boot architecture for avoiding bootkits and rootkits threats. It has the potential to eliminate kernel-level malware from your network.