Apple has quietly removed the entire "Doorbell" category from its roster of current and future HomeKit accessories, suggesting that once-promised upgrades by August and Ring are at least in purgatory.

The change appears to have happened sometime this week. Only one item was listed under the category, the August Doorbell Cam.

When Apple introduced the Home app for iOS 10 during WWDC 2016, video doorbell support was prominently demonstrated, hinting that a flood of compatible products might be around the corner. The company indicated that people would be able to watch live feeds, use an intercom, and even unlock their door, all from a Home app notification.

August and Ring soon promised to upgrade their doorbells, but years later neither has delivered software upgrades. The latter even reaffirmed its commitment to upgrading the Ring Pro and Floodlight after its takeover by Amazon, even though Amazon's Alexa is a rival smarthome platform.

It's not clear what hurdles have prevented HomeKit support. One possibility is the heavy encryption Apple demands, since while the platform now supports both software and hardware for that task, it could be that August and Ring have had trouble minimizing lag.

Doorbells are typically expected to deliver audio, video, and other data with as little lag as possible. A long gap could at best make for an awkward social situation, and at worst mean that a criminal gets away without his face on camera.