# What's New?

### WebAR SDK v2.1.0

**Release Date:** January 2026

#### New Features

**Face Tracking Lifecycle Callbacks**

Monitor face detection state in real-time with new callback APIs.

**New APIs:**

* `SetFaceFoundCallback(callback)` - Fires when a face is detected
* `SetFaceLostCallback(callback)` - Fires when a face is lost
* `IsFaceTracked()` - Check if face is currently tracked
* `GetFaceTrackingState()` - Get current state ('FOUND' or 'LOST')
* `RemoveFaceFoundCallback(callback)` / `RemoveFaceLostCallback(callback)` - Remove callbacks

**Usage:**

```javascript
WEBARSDK.SetFaceFoundCallback((faceInfo) => {
  console.log('Face detected!');
  showARContent();
});

WEBARSDK.SetFaceLostCallback(() => {
  console.log('Face lost!');
  hideARContent();
});

if (WEBARSDK.IsFaceTracked()) {
  // Face is currently visible
}
```

**Key Features:**

* Callbacks fire on state transitions (not every frame)
* Built-in debouncing to prevent flickering
* Access to face position, rotation, scale, and mouth openness
* Late registration support - callbacks fire immediately if face already tracked

***

**Tracking Status API (Surface & World Tracking)**

Query the current tracking state for Surface and World Tracking modes.

**New API:**

* `GetTrackingStatus()` - Returns current tracking state

**Usage:**

```javascript
const info = WEBARSDK.GetTrackingStatus();

if (info) {
  console.log('Status:', info.status);        // "Tracking", "Anchoring", etc.
  console.log('State:', info.state);          // 0-3
  console.log('Is Tracking:', info.isTracking); // true/false
}
```

**Tracking States:**

* `0` - Idle
* `1` - Anchoring/Initialising
* `2` - Tracking (active)
* `3` - Relocalising

***

#### Bug Fixes & Improvements

**Windows Touchscreen Laptop Detection**

Fixed device detection for Windows touchscreen laptops (Microsoft Surface Pro, Surface Laptop, etc.). These devices are now correctly identified as desktop devices, preventing unwanted motion sensor permission prompts.

**CSS Framework Compatibility (Face Tracking)**

Fixed face tracking compatibility with CSS frameworks like Tailwind and Bootstrap. The SDK now properly handles aspect ratio constraints, preventing horizontally stretched faces and improving tracking accuracy.

**Gyro Initialization**

Improved gyro sensor initialization for more reliable tracking startup.

***