Eric and team – great discussion on HN about tether, an app built by zackb so he could get all macOS continuity features on Linux. He has an iOS app as well. Some of the ideas and libraries he built / is using might help with expanding iOS support in Pebble OS.
iOS Companion App implements some capabilities that we can consider for adoption by Pebble’s iOS Companion App: Tether - Linux Companion App - App Store