Using Microsoft's current naming convention for Windows 10 releases, that implies the coming Redstone 2 build will be a March 2017 deliverable.
I asked some of my contacts and they confirmed that March 2017 is, indeed, the current ship target for Windows 10 Redstone 2. (I asked Microsoft officials for comment, and unsurprisingly, they had nothing to say on the matter.)
So far, the Insider test builds of Redstone 2 haven't revealed any of what hopefully will be some of the more major features coming in the next Windows 10 release. The test builds so far have been mostly vehicles for rather minor feature tweaks.
For those wondering whether a 1703 ship target implies anything about dates for Microsoft's Build 2017 event, I don't believe so. Microsoft doesn't need to use its annual developer show to launch a new release, as developers already are working with early versions of new Windows 10 releases on a regular basis.