Trådfri uses COAP and on Android we use Californium lib. On iOS we need to find an alternative. We use lots of code through Kotlin multiplatform, so just need implementation for sending COAP messages.
Android specific code for COAP is only 169 lines calling to Californium. So with the right library, it is not much work for iOS. All other code is shared and should work.
More important is that we need permission (statement) from IKEA to prevent app removal by Apple.
See our post Apple legal issues [Resolved]