According to ZDNet Microsoft plans to start rolling out Windows 10 Fall Creators Update October 17th.

Expect this to be one of those long term roll outs, with machines being updated in waves.

 

Microsoft still has yet to deem the Fall Creators Update as being feature-complete (or, as many of us still prefer to call it, RTM), but does plan to do so in September, hence its 1709 nomenclature. Microsoft also will designate a September build of Windows Server 2016's first feature update (1709) as its "launch" candidate, as the company plans to announce at its Ignite conference in late September. As "launch" and "release" don't always coincide with Microsoft products, Server 1709 also will likely begin rolling out to users in October.