Originally code-named Windows 10 Threshold 2 and subsequently unofficially renamed many times by the press, Microsoft seems to be settling on Windows 10, Version 1511, build 10586, as witnessed by the download notification:
Note that there’s no reference to build 10586.3, the build I discussed yesterday. You may or may not be able to see that build on your July 29 RTM Windows 10 build 10240 PC. Apparently it’s rolling out slowly.
Users can manually upgrade to the latest version of Windows 10 now, or wait and have it done for them overnight
There are full ISOs available for download — Multiple editions, Education, Enterprise, Features on Demand — from MSDN, if you’re a subscriber. All are identified as Windows 10, Version 1511.
Windows honcho Terry Myerson has an overview on the Windows Experience blog. According to Myerson, “Windows 10 is already actively running on more than 110 million devices including 12 million business PCs, and is compatible with the past while embracing our new way of working… with this free update we have reached the point in the platform’s maturity where we can confidently recommend Windows 10 deployment to whole organizations.”