Wristcam works with Apple Watch Series 6, SE, Series 5, Series 4 or Series 3.
For the optimal Wristcam experience, you will need an Apple Watch Series 4 or greater. This means if you decide to use the Wristcam with the Apple Watch Series 3 (or below) they use Bluetooth 4.2. What does that mean? You will note a slower connection. Therefore, you may expect a slower response time from the app from connecting the device to preview.
The Apple Watch Series 6 and SE haven't changed much in terms of how it will communicate with Wristcam; both use Bluetooth 5. We have already upgraded Wristcam to support Bluetooth 5 as well. We have access to the new Watch OS so the software changes will already be compatible with the new Watch software (and any other Apple Watches that update to the new OS).
Please note that any Apple Watch Series 4 and later band connection hasn't changed even though the screen size is larger, and all old bands for the Apple Watch will continue to be compatible with the newest versions. This means that the 38mm Wristcam will fit the 40mm Apple Watch and the 42mm CMRA will fit the 44mm Apple Watch.