Windows 11 is now the operating system of choice for over 400 million monthly active devices. Windows Central reportedly is getting eyes-on with "Microsoft internal data" that has Windows 11 on track to hit 500 million monthly active devices in early 2024.

Microsoft launched Windows 11 in October 2021, so it has taken two years to reach the 400 million milestone, versus Windows 10 only taking just over 12 months to hit 400 million users. Windows 10 had reached a huge 600 million devices just a few months after the two-year mark, so Windows 11 is a little behind when it comes to operating system upgrades and adoption rates.
We should note Windows 11 is only supported by CPUs that were released in 2018 and newer, as well as with devices with TPM security chips. Windows 11 had higher minimum system requirements than previous operating systems, with modern chips and TPM (Trust Platform Module) support.
TPM is a physical chip that's used to store encrypted information, but it also lets you use a secured boot environment. With TPM, we have BitLocker storing the encryption key and your Windows Hello biometric security, meaning Windows Hello is secure at a hardware level.
The difference between Windows 11 and Windows 10 adoption: Microsoft launched Windows 10 as a free update to all Windows 8.1 and Windows 7 PCs... advertised as a free upgrade for a limited time, moved users into the arms of Windows 10 quicker than previous operating systems. Microsoft was wanting to get users off and away from Windows 7 and Windows 8 and into Windows 10. But, once you're using Windows 10, there's no huge urge to upgrade to Windows 11... and maybe that's why those numbers aren't as high as Windows 10 at the same two-year mark.