For those of you interested, this was announced today:
"Windows Central understands that the first major update for 2017 (codenamed Redstone 2) will release in the early part of 2017. The second major update scheduled for 2017 is codenamed “Redstone 3”, which I’ve heard is being targeted for a Summer 2017 launch.
This will leave around 4-6 months between Redstone 2 and Redstone 3, which is similar to the update pattern that the Threshold update wave followed. Redstone 3 will likely be a much smaller update compared to Redstone 2, much like Threshold 2 was to Threshold 1.
Microsoft is currently in the midst of Redstone 2 development, with the latest internal builds now being compiled around the 14900 range. It shouldn’t be too long before Insiders begin receiving Redstone 2 bits for testing, as Microsoft is keen on getting the latest bits out for testing as soon as possible for maximum bug catching and feedback.
Of course, considering we’re still several months away from any updates being ready for the public, schedules and timings could easily change. However, one thing is definitely clear; Microsoft wants two major updates out in 2017, which is great news for Insiders and consumers who want to stay updated with the latest features and enhancements from Microsoft."