In the afternoon hours of July 6th, a build with the tag 10500.0.150706-1800.th2 has been compiled. The "th2" lab is speculated to be the lab which we'll eventually receive "Redstone" from once it gets finished. Although this lab has existed for quite some time, the significant factor is the big build number jump that happened recently.
The fact that a build jump like this has happened also implies that Windows 10's RTM code has been authored and will now be built upon, delivering us new features based on the Windows-as-a-Service (WaaS) concept.
Another bit of speculations revolves around the final build number of the Windows 10 RTM. As "th2" jumped to 10500, it should be safe to say that its build number won't go past that.
Source: BuildFeed
