Wifi Calling

Still his question is unanswered...there is no where mentioned on the link what he asked for...

@Harpreet, it answers everything except the last part..so, If am not wrong, as its network based feature, it will require active data plan..(note: active data plan)

@Sidhabhi, he asked will he be able to make calls by using WiFi calling feature if he runs out of calling balance or if the tariff is not active.... So, specifically this thing was not mentioned on the link, as I trust many other ppl wanted to know this thing... Though as per my understanding one should have active tariff and balance on their phone to make calls as all the calls will get charged basis their network provider tariffs....
Note: It requires active broadband connection along with active talktime plan and not just the data plan....