This week can go Windows 10 build 10550
The end of this working week may result in a new version of Windows 10 Preview. Ol Gabe himself confirmed today on Twitter that they are currently testing an Assembly under the number 10550, which is seen as a potential candidate for the distribution channel Fast among the participants of the insider program.
One should not expect serious changes from the point of view of functions, taking into account the contents of the previous version 10547, which is available to insiders since the end of last week. All changes in Assembly 10550 is likely focused on bug fixes and performance optimization.
@callum90ish 10550 Microsoft is in the ring now. Only a few builds newer than the last flight but may go out to Fast WIP. We’ll see.
— Gabriel Aul (@GabeAul) 24 Sep 2015
Please note that a Microsoft representative did not provide any predictions about the timing of the release of a new build, and talk about the release at the end of this week are purely the result of speculation.