It's been a long time since HoloLens last received a major Windows 10 update. The last was in 2016 with the Anniversary Update, and hasn't received any feature updates since. Today, that all changes however, as Microsoft has finally released a preview build of Windows 10 Redstone 4 for HoloLens!

Installing Redstone 4 for HoloLens is a little different from normal Insider Preview builds. Instead of getting it through Windows Update, you have to manually flash a recovery file with the build via the Windows Device Recovery Tool. This is likely because there is no direct upgrade path from the Anniversary Update to Redstone 4.

This preview is available to all HoloLens users, however, please note that installing this preview will erase all of your content and restore your device to factory settings. Like any pre-release software, you may encounter bugs and other issues along the way. For this reason, Preview builds are made for people who know their way around HoloLens and don't mind frequent updates with significant changes.

Microsoft has detailed how to install the preview via the Windows Device Recovery Tool, which you can check out here.{.nofollow}

Regarding the update, here's what's new!

Auto-placement of 2D and 3D Content on launch

Fluid app animation

2D app horizontal resize with reflow

Expanded voice command support

Updated Holograms and Photos apps

Improved mixed reality capture

Improved audio immersion

File Explorer

MTP support

Captive portal network support during setup

Spatial mapping improvements

Automatic selection of focus point based on depth buffer

Holographic reprojection modes

App tailoring APIs

Use multiple AD user accounts on a single device

Change Wi-Fi network on sign-in

Unified enrolment

Mail Sync without MDM enrolment

New OS name when Commercial Suite features are enabled: "Windows Holographic for Business"

Configurable setup

Windows Configuration Designer

Bulk AAD token support

Developer CSP

Assigned Access for Kiosk Mode

OOBE diagnostics

Local account indefinite password expiry

MSM sync status and details

The build available for HoloLens is 17123, which is a fair bit older than the builds currently in testing with Insiders on desktop. It is likely that Microsoft will release more RS4 builds for HoloLens over the coming weeks, so stay tuned for that.