Microsoft has offered a miniscule concession to users determined to install Windows 11 on PCs that dont meet its minimum hardware requirements: you will be able to do it, but on your own head be it should things go wrong.The apparent moderation of its previously hardline upgrade policy appeared on a support page update which lists the numerous disadvantages of pressing ahead with a Windows 11 on an unsupported system.These include unspecified compatibility problems, and a watermark noting a PCs non-compliant status that will appear on the Windows 11 desktop. More significantly, it states:If you proceed with installing Windows 11, your PC will no longer be supported and wont be entitled to receive updates.This is unambiguous no security updates. And thats in addition to the rather alarming warning that any damages to your PC due to a lack of compatibility arent covered under the manufacturer warranty.Those are serious gotchas, the same ones Microsoft has been warning about for some time. Only a week ago, a blog by Microsoft senior program manager Steven Hosking described the most important element of the Windows 11 requirements, support for Trusted Platform Module (TPM) 2.0, as non-negotiable. That remains the case.Not sugarcoating itWhat has changed? Despite some optimistic news reporting on this issue, nothing. Microsoft doesnt want users to upgrade to Windows 11 on unsupported hardware, but is now acknowledging that some people will push ahead regardless. That being so, it wants to tell them what might happen, so they cant say they werent warned.The date Windows 10 is due to stop receiving updates, Oct. 14, 2025, remains the same. Upgrading to Windows 11 without meeting the hardware requirements wont change the negative consequences of this. Nor does the update explain how users can bypass the minimum requirements, should they choose to do so.Importantly, users who regret upgrading will only have ten days to revert to Windows 10. After that, the files enabling this function will be deleted to save disk space, and the go back button in Recovery options will disappear.Microsoft also doesnt elaborate on what it means by Windows 11 compatibility issues, so this is a matter of guesswork. However, its possible to imagine that new features that assume a TPM is available could cause instability on a machine lacking this facility. It could also affect drivers for older hardware no longer supported in Windows 11, although this would be likely to be an issue over the longer term.Meet the TPMMicrosofts minimum requirements for Windows 11 cover several hardware components, including having enough RAM and a powerful enough microprocessor. But the most contentious issue is whether a PC contains or supports a Trusted Platform Module (TPM), specifically version 2.0, released in 2014.A TPM is a secure enclave for storing data such as cryptographic keys, certificates, and biometric information fundamental for the security of a PC, including those required for low level PC checks such as Secure Boot, or for the use of Microsofts BitLocker in its more secure mode. Having one is somewhere between a good idea and essential, as more and more software systems going forward assume one will be there at the root of trust. For a summary of the arguments in favor of upgrading to a system with TPM 2.0, Hoskings blog is a good place to start.When it comes to TPMs and Windows, PCs divide into three categories, the first of which supports the functionality using a TPM 2.0 chip installed on the motherboard. The second doesnt have a TPM chip, but can either have one installed using a chip upgrade kit from the motherboard vendor or can have TPM enabled through firmware at UEFI level. The third are PCs that dont support either option, which means they cant be upgraded to Windows 11 without a registry hack.Intel and AMD PCs from about 2017 onwards should support a hardware or software TPM 2.0, while earlier ones going back to Intels Skylake 6th generation in 2015 might do so, depending on the specific processor and support at motherboard and UEFI level.Extended supportFor anyone who doesnt want the risk of a Windows 11 upgrade on unsupported hardware, or just prefers Windows 10, after October 2025 the most secure option will be to pay for an Extended Security Updates (ESU) subscription at an unconfirmed cost of $30 per annum for individuals. That way, updates wont disappear abruptly, putting the PC in peril as vulnerabilities pile up over time.Not surprisingly, a lot of users are happy with the status quo and dont feel they should be forced to upgrade to Windows 11 or to pay to remain on Windows 10. This, arguably, is Microsofts fault. It hasnt always clearly explained the benefits of its minimum requirement. That, unfortunately, includes explaining why TPM 2.0 is a good idea, and how its software increasingly depends on it for security.