# NRSDK 1.9.1

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**Download** [**NRSDKForUnity\_Release\_1.9.1.unitypackage**](https://nreal-public.oss-us-west-1.aliyuncs.com/download/NRSDKForUnity_Release_1.9.1/NRSDKForUnity_Release_1.9.1.unitypackage)
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**What's New:**

* Implemented new Hand Tracking underlying algorithms that greatly improved hand tracking performance
* Added support for **0Dof Stable** Mode `NRHMDPoseTracker.ChangeTo0DofStable` that enables the display's tag-along behaviour depending on the current view
* Added support to record environment and in-app audio simultaneously. See **AudioState -> ApplicationAndMicAudio** in **RGBCamera-Record** scene for details
* Added brightness-related native APIs in `NRKernal.NRDeviceSubsystem`

**Improvements:**

* Improved 3DoF controller tracking and 3DoF head tracking on Nreal Air
* Improved speed switching between different tracking mode

**Bug Fixes:**

* Fixed occasional SDK launch failure
* Fixed recorded audio/video out of sync problem (audio speed is accelerated)
* Fixed the issue that the microphone's recording volume is too low
* Fixed RGB Camera's capturing/recording offset
* Fixed controller drift due to 0DoF/3DoF/6DoF tracking mode switch
