Until the release of Home Assistant Core 2021.6, Philips Hue and Home Assistant already had a solid integration that didn’t rely on any cloud services and could function without either being connected to the internet. Using a local API, Home Assistant Core would simply ask the Philips Hue bridge what the state of any connected lights and sensors were. While local control is in any case a good thing and preferable to cloud control, the way the Philips Hue integration was handled thus far wasn’t perfect.
The process just described is called polling, and it can lead to slight delays in response times because the Philips Hue integration with Home Assistant required the latter to check the hub for any changes. The alternative to polling, is pushing. As the name suggests, when pushing is used, the device in question, in this example a Philips Hue hub, will push a state change to Home Assistant as soon as it occurs.
As of Home Assistant Core 2021.6, the Philips Hue integration will support local pushing, a significant upgrade on local polling. From a user’s point of view, this change has no negatives. The configuration does not have to be adjusted, and response times will increase just by updating to the latest version of Home Assistant Core.