That was weird. Thanks for the link.It's not down, for some reason they decided to rename it...
WiFi Calling | Make Voice Call Over WiFi with Vi WiFi Calling | VoWiFi
WiFi Calling: Vi wifi calling lets you make & receive voice calls over the wifi network on your mobile. Enable Voice over wifi settings on your phone and enjoy wifi calling.www.myvi.in
Yes it isIs this available in Mumbai ?