Upcoming Lumia flagships will not ship with Windows 10 Mobile TH2 RTM

Zac Bowden

It’s common knowledge at this point that Microsoft is currently working on Threshold 2, the next update for Windows 10 which is set to bring a small number of new features and fixes to the table. Threshold 2 will be both a desktop and mobile release, but considering Windows 10 Mobile hasn’t officially launched yet, the Threshold 2 RTM will be the first official public build of the operating system.
For those who are up to date with news regarding Threshold 2, you’ll know that Threshold 2 is set to launch in early November, but that contradicts the fact that Microsoft is planning to launch new Windows 10 Mobile flagship devices in early October, a whole month before Windows 10 Mobile is set to be ready. Mary Jo Foley was first to bring up the idea of Microsoft shipping a build that wasn’t the Threshold 2 RTM, but I was curious to see if this could actually be the case. So what exactly is happening here?
Upon speaking with my contacts, I’ve learned that Microsoft is planning to ship a Threshold 1 (TH1) build of Windows 10 Mobile on new Lumia handsets launching in October. I believe the build number will be build 10240, similar to the Windows 10 desktop RTM build number, but will have a number of patches and fixes in place to help make the experience smooth and complete, at least until Threshold 2 rolls out publicly.
Microsoft has been working on these patches for mobile build 10240 behind the scenes for weeks now, since build 10240 was compiled in fact. Much like delta updates, the build of Windows 10 Mobile that will ship on new Lumia handsets will have an increased delta build number; 10240.16xxx. Now, before people jump the gun and proclaim the new Lumia handsets are launching with pre-release software, let’s clear things up.
Build 10240 is the initial Windows 10 RTM across the board, that means for mobile too. The codebase chosen was signed off, but since Microsoft decided to wait until Threshold 2 to ‘officially’ release Windows 10 Mobile, they decided not to announce a Windows 10 Mobile RTM as it didn’t make sense to. Either way, build 10240 for Windows 10 Mobile shares the same attributes as a normal RTM build does; support, patches, access to the stable channel for app updates (not insider), and ultimately no time bomb. So if you want to get real technical, build 10240 is not pre-release software. In a world in which Windows is now a service, the fine line between pre-release software and an RTM is blurred anyway.
For everyone else, Windows 10 Mobile will launch with the Threshold 2 RTM upgrade in November, delivered via Windows Update like expected. Build 10240 for Windows 10 Mobile is not far different from Threshold 2 anyway. Minus a few additional settings and options coming in TH2, the experience is pretty much identical. So if you’re planning to buy a Lumia 950 or 950 XL in October, I wouldn’t be too worried. Besides, the wait for Threshold 2 will not be long once the Lumia 950 and 950 XL starts shipping.