http://betanews.com/2015/07/15/windows-10-insider-preview-build-10240-has-a-special-purpose/
Earlier today The Verge stated that Windows 10 has been finalized, and Build 10240 was the version of the new OS that Microsoft has selected as the final Release To Manufacturing (RTM) copy. While Microsoft has just released that very build -- after briefly suspending updates -- it has neither confirmed nor denied its RTM status. The company has made it clear however, that Insiders can expect still more builds before the full version is released to the world at large on July 29.
However, what’s interesting is that Build 10240 isn’t an ordinary release. It has the bug fixes you’d expect from a new build, and the desktop watermark has been removed, but that’s not what’s most significant about it. RTM or not, Build 10240 serves a vital purpose.
For the first time since the Insider program began, Microsoft is releasing the new build to both the Fast and Slow rings simultaneously. It’s not making it available in ISO format, and the build is also only available to Insiders who are already running a preview version (10074 or newer). In fact, Microsoft has removed all ISOs and keys, preventing anyone from cleanly installing the new OS from scratch. From now on, any new builds, and updates, will only be available through Windows Update.
That’s because Build 10240’s primary raison d'etre -- as confirmed to me by a Microsoft insider -- is to test the upgrade process in advance of the roll out in two weeks’ time. Microsoft could offer Build 10240 as an ISO, but as Windows Insider chief Gabriel Aul himself says, "we really need people to be using the upgrade path".
Rolling out an upgrade to as many Windows Insiders as possible (5 million + potential systems), will give Microsoft a clear idea of how smoothly the roll out process will likely go on July 29 and allow the software giant to make further tweaks to the "release pipelines and processes" it’s been preparing over the past couple of days.
Windows Insiders have helped Microsoft shape the OS, and now by installing Build 10240 they are helping to ensure -- in theory at least -- that Microsoft delivers as smooth a roll out as possible on the big day.
