https://arstechnica.com/gadgets/2021/08/windows-11s-months-long-public-rollout-begins-on-october-5/

Windows 11 is no longer merely "coming this fall." Microsoft will begin releasing the new operating system to the public on October 5, starting with newer PCs (and PCs being sold in stores) and then rolling out to other supported systems over the next nine or so months. The company also says that the Amazon-powered Android app support that's coming to Windows 11 won't be ready for public consumption at launch; Microsoft will offer "a preview [of Android apps in the Microsoft Store] for Windows Insiders over the coming months."

Like recent Windows 10 updates, Windows 11 will have a phased rollout through Windows Update—most PCs won't begin to see and automatically install the update on October 5. Microsoft says that new PCs will be the first to upgrade, followed by older compatible PCs, "based on intelligence models that consider hardware eligibility, reliability metrics, age of device and other factors." As with Windows 10 updates, you'll be able to download an ISO file to initiate the upgrade yourself (Microsoft also offers tools like the Windows Update Assistant to manually trigger upgrade installs, which we assume it will do for Windows 11, too). All compatible PCs should be offered the update by mid-2022.