Microsoft has already begun wrapping up the first major revision to its Windows 10 operating system, known internally as Redstone 1 and externally as the Anniversary Update. It releases to the public on August 2nd, after just over 1 year of development time, bringing changes ranging from Cortana improvements, improved performance, Microsoft Edge extensions and much more.
It appears that Microsoft has already begun the work on its next major revision, known only as Redstone 2. This next milestone is set to be focused on Windows 10 Mobile, to arrive publicly to the masses in 2017, around the supposed launch of the rumoured "Surface Phone". Nothing is concrete as yet, though.
BuildFeed, which tracks internal builds, has brought up the build 14894. The current Redstone 1 build is 14393, with a revision of .5, and the company seems set on releasing this to the public, making 14894 the next major build after Redstone 1 is released. There are no details surrounding the build, although, it is likely that Microsoft is just laying the groundwork to begin getting things ready to roll out to Insiders later this year. Some have already begun to speculate that we could see the next major build around mid-August.
14894 was compiled for both PC and Mobile on July 27th. With it being such a large leap from 14393, it could already include new features and/or major changes.
We'll keep an eye on the latest builds and let you know of any further developments.