Broken hand tracking APIs due to outdated SDK versions

What is Hand Tracking in XR?

Hand tracking allows users to interact with digital content using natural hand gestures, without the need for controllers. This technology is central to immersive experiences in Augmented Reality (AR) and Virtual Reality (VR), providing more intuitive and accessible interaction.

It works by using:

Depth sensors, cameras, or machine learning models to detect hand joints.
APIs provided by platforms like Meta Quest, HoloLens, ARKit, ARCore, and OpenXR.
SDKs from the respective hardware vendors to access real-time hand tracking data.

What Happens When SDKs Are Outdated?

Using outdated SDKs can lead to broken or non-functional hand tracking APIs. These SDKs often:

Lack support for latest hardware capabilities.
Are incompatible with new OS or firmware versions.
Use deprecated functions or data structures.
Miss critical bug fixes, causing instability or crashes.

Common Symptoms of Broken Hand Tracking APIs

Hands not being recognized or tracked by the system.
Incorrect joint positions or missing joints.
Laggy or unstable tracking behavior.
Incompatibility errors during build or runtime.
APIs not found or deprecated warnings in the IDE.
Gestures not registering or being misinterpreted.

Root Causes

1. Outdated SDK or Runtime

Cause: Using an older SDK version incompatible with the latest platform runtime (e.g., Meta SDK 1.x on Quest firmware v63).
Fix: Upgrade to the latest SDK matching the target runtime or platform version.

2. API Deprecation

Cause: Using functions or components that have been deprecated in newer SDK versions.
Fix: Refactor code to use updated API endpoints and check changelogs for migration guidance.

3. Mismatch Between SDK and Unity/Unreal Engine Version

Cause: The SDK was built for an older engine version and may break with new XR pipeline changes.
Fix: Update both the engine and SDK together. Use compatibility matrices provided by SDK vendors.

4. Firmware and SDK Incompatibility

Cause: Device OS or firmware updated, but the SDK used does not support the new runtime.
Fix: Ensure the SDK version you’re using is compatible with the current headset firmware.

5. Incorrect Manifest or Permissions

Cause: Some hand tracking SDKs require specific manifest entries or permissions.
Fix: Add required flags in AndroidManifest.xml (for Android/Quest) or Info.plist (for iOS/ARKit).

Examples of SDKs with Hand Tracking Features

Platform	SDK / API
Meta Quest	Meta SDK, OpenXR, Interaction SDK
HoloLens	Mixed Reality Toolkit (MRTK)
Android	ARCore SDK for Unity/Unreal
iOS	ARKit + RealityKit
Cross-Platform	OpenXR Hand Tracking Extension

✅ Best Practices to Prevent API Breakage

Practice	Benefit
Regularly update SDKs	Access to latest features and bug fixes
Monitor deprecation notices	Future-proofs the application
Use abstraction layers (like MRTK or XR Interaction Toolkit)	Minimizes code changes during SDK upgrades
Test on target hardware frequently	Detects SDK/hardware mismatches early
Review changelogs	Stay informed about breaking changes

Debugging Broken Hand Tracking APIs

Steps:

Check SDK version vs platform firmware
- Visit the SDK’s official page to match versions (e.g., Meta SDK Release Notes).
Look for deprecated APIs in logs
- IDE or runtime logs often show warnings or errors for outdated usage.
Verify camera permissions
- Ensure AR apps have permission to use the camera or depth sensors.
Enable hand tracking in platform settings
- Example: In Meta Quest settings or Developer Hub.
Test in isolation
- Run minimal demo scenes to isolate whether the issue is SDK-related or logic-related.

Updating Example: Unity + Meta Quest

Problem:

Hand tracking not responding after Quest firmware update.

Solution:

Update Meta Integration SDK to the latest version (e.g., from v47 to v63).
Enable Hand Tracking Support under Project Settings > XR Plug-in Management > Oculus > Hand Tracking Support.
Replace deprecated APIs (e.g., OVRHand.GetTrackingConfidence() to OVRHand.TrackingConfidence property).
Update AndroidManifest.xml to include camera and tracking permissions.
Test and validate using the latest Meta Interaction SDK samples.

Real-World Use Case

AR Training App (HoloLens)

An enterprise training app used MRTK v2.4. After a Windows Holographic OS update, hand joints started behaving erratically.

Fix:

Upgraded to MRTK v2.8
Updated Unity to LTS version
Migrated hand logic to new XR SDK structure
Resolved tracking lag and joint misplacement

Future-Proofing Your Hand Tracking Integration

Use OpenXR where possible for cross-platform support.
Subscribe to SDK release notes and XR developer community forums.
Avoid hard dependencies on SDK-specific features unless absolutely necessary.
Regularly test builds on multiple firmware versions and hardware models.
Use feature detection instead of assuming availability (e.g., XRHandSubsystem availability checks).