"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Initiates Replacement Program for 3rd Generation Apple TVs With Wi-Fi Connectivity Issues
Apple has determined that a very small number of Apple TV (3rd generation) products might experience one of these Wi-Fi related connectivity issues:Apple technicians are authorized to replace affected products for two years from the original date of purchase at no charge to the customer after verifying that the devices are running software version 5.2.1 and that there are no third party interference issues.
Cannot locate network
Unable to join network
Dropped or intermittent connection.
The Apple TVs experiencing connectivity problems feature the following serial numbers:
The third generation Apple TV, which features support for 1080p video, was first released in March of last year. It was later tweaked in late January to include a smaller A5 chip.
Update: According to several readers, Apple has acknowledged that it initially erred in referring to the character pairs appearing the third and fourth positions of the serial number. The listed pairs would actually occur in the fourth and fifth positions.