https://www.theregister.co.uk/2017/08/04/apple_drops_homekit_chip_requirement/

Analysis Apple has made a huge reversal in its HomeKit smart-home technology, in an effort to keep up with Amazon and Google.

The iPhone giant has insisted for years that any third parties wishing to create HomeKit-compatible products have to include a special Apple-specified chipset in order to authenticate, connect and transfer information securely.