The man has updated the Wifi calling app in order to be compatible with Android 4.0 (Ice Cream Sandwich). This is what tytung says about it.
The latest WiFi Calling packages which support both MAGLDR and cLK with working mobile data.Looks like the development over the HD2 is currently growing, previously we are presented with Android Jelly Bean for HTC HD2 now this.
According what I have read on the forum, the process of bringing the app working on ICS takes about a month, also all the latest bugs reported are already fixed. Therefore you can expect a flawless Wifi calling experience on HTC HD2 running on ICS now.
Visit the original thread to download links and more details about this. See you in the next posts.