Microsoft (MSFT) is putting the finishing touches on Windows 10 three weeks ahead of the official launch on July 29, with a release to manufacturing (RTM) build expected in days.

Should Microsoft issue a Windows 10 RTM build, it would signal the vendor’s stamp of approval that the code is stable enough for OEMs to load onto their machines and devices.

A number of online reports this week have said the vendor is just about set with an RTM build of its much-anticipated new operating system. When the Windows 10 RTM build is ready, Microsoft will issue a final version to its PC OEMs ahead of the public release date.

The Verge reported that Windows 10 RTM copies already have been found online but pointed out that unlike earlier RTM Windows editions, this one is unique owing to Microsoft’s Windows-as-a-Service model that will produce regular and more frequent updates to the operating system. Upcoming updates are expected to include extensions for Microsoft’s Edge browser and app updates for baked in Windows 10 applications.

Neowin also reported that Microsoft will sign off on a RTM version this week.

Once the RTM build is completed, the vendor has but three weeks to clean up any bug fixes prior to the July 29 grand opening. It will release the final version to Windows 10 testers followed by a general availability rollout of the OS in waves.

While the last official Windows 10 build received by testers on July 2 was 10162, ComputerWorld reported signs that build 10163 included references to Thursday, July 9 as an RTM sign off date. For example, WZor said it saw a reference in the operating system’s Calendar app to that date and BuildFeed pointed out that the 10163 build was tagged as from “th1,” also a reference to the internal code name for Windows 10. And, a following build, 10176, also included the “th1” marker, according to BuildFeed.