https://www.techradar.com/news/hololens-20-could-be-delayed-by-windows-core-os

Microsoft’s HoloLens 2.0, the update to its original HoloLens augmented reality headset, might be delayed due to the slow development of Windows Core OS, Microsoft’s next generation operating system.

The news follows reports that the Surface Hub 2, Microsoft’s smart whiteboard, has also been delayed until 2020 due to development of Windows Core OS being slower than anticipated.