With Windows 10, Microsoft is striving to release two major updates for Windows 10 every year, except for this year as the company decided to delay Redstone 2 until early 2017, as I exclusively reported several months ago. It's always hard to pinpoint an exact time-frame for software launches as they're constantly slipping, but I've been hearing over the last couple of months that March 2017 is the target-month for Redstone 2's launch.
A user on Twitter by the name of h0x0d, who is known for leaking all kinds of Microsoft goodies has spotted references to a "Version 1703" in the latest Redstone 2 Insider builds. This matches what I've been hearing, but it does seem curiously early especially given all Windows 10 releases so far have launched in either the middle of the year or late in the year. In regards to the second major update coming in 2017 codenamed Redstone 3, expect that to launch in the summer.
That leaves a considerable gap between Redstone 3 and the next major update for Windows 10, which I'm told is codenamed Redstone 4 and coming sometime in 2018. This leads me to believe Microsoft has some big plans with Redstone 4, as its development time will be considerably longer compared to the releases coming in 2017. Of course, since we're talking about updates that are over a year away here, things could change.
Regardless, with Redstone 2 being less then half a year away, it shouldn't be too long before Insiders start seeing much larger features show up in Insider builds to test. Microsoft is slowly building out Windows 10, and with these major updates scheduled over the next couple of years, the company should keep up with the competition.