Microsoft is planning to release Windows 10 on July 29th. So they have to hand over the RTM build of Windows 10 as soon as possible to their partners for testing before the release. According to several reports that emerged online, Microsoft is planning to sign-off Windows 10 RTM later this week. Wzor also posted a screenshot of Calendar app showing RTM Sign-off date as July 9th. Also, Microsoft is testing Windows 10 Build 10176 from the th1 branch as the first Release Candidate build.

For Windows Insiders, Windows 10 RTM will not make that much difference from their current build apart from improved stability of the overall performance and bug fixes. Microsoft is planning to release new builds with many new features even after Windows 10’s release on July 29th.

Source: http://microsoft-news.com/windows-10-rtm-sign-off-happening-later-this-week/