https://www.theverge.com/2017/11/1/16589418/ikea-apple-homekit-tradfri

After making a false start back in August, Ikea's TRÅDFRI lights will now integrate with devices compatible with Apple's HomeKit smart home standard. The free software update makes Ikea's low-cost smart lights manageable from within Apple's Home app, but TRÅDFRI dimmer switches and other accessories are not yet supported. The news was first spotted in the Swedish media and confirmed on Ikea's Facebook page.

Owners of the TRÅDFRI gateway can find the device's 8-digit HomeKit code in the just released 1.2 version of the Ikea TRÅDFRI app, or printed on the underside of gateways sold more recently. Unfortunately, the promised Google Home and Amazon Alexa compatibility isn't live yet, and Ikea's Facebook page doesn’t offer an expected date.