Microsoft has released Windows 10 Mobile build 15240 to the Slow ring for Insiders. As usual, the company hasn't made any kind of announcement about it, or updated its original blog post.
Build 15240 RSS
Today, Microsoft published a new Windows 10 SDK Preview, build 16267, which is higher than the current Fast ring release, build 16257. There's also a new Mobile Emulator Insider Preview, build 15240.
Microsoft has announced the rollout of Windows 10 Mobile Insider Preview build 15240 to phones in the Fast ring - but not everyone will be able to install the new build immediately.