The release of Redstone 1 this year for Windows 10 could be delayed until July if information released in new documentation is anything to go by. According to new material surrounding UWP apps on Xbox One, the video console will be rocking Windows 10 version 1607, which notes a specific version of the OS to be released in July this year.
As spotted by WinBeta (the page is now removed):
"Xbox runs Windows 10, version 1607, which means that it shares the same core operating system as other devices in the Windows 10 family: desktop, mobile, and HoloLens. But, because this is the first release of the Universal Windows Platform (UWP) on Xbox, there are some feature areas that haven't reached the same level of support on Xbox as they have on other devices. In this topic are details on some of the feature areas that your UWP app might use that don't currently function as fully on Xbox. All APIs are callable and will fail gracefully if they're unsupported. As we flight and service Windows, we'll continue implementing, testing, and bugfixing until all of the Universal device family API surface is fully operational on Xbox."
Of course, nothing is set in stone until it's officially rolled out. Build 2016 is also just around the corner so we'll have to hold out and see what Microsoft has planned for the event.