Wifi Calling questions

Can anybody tell me if wifi calling also support SMS over wifi?

And are there any international roaming restrictions is using it? As a regular international traveler, being able to call from my phone (over wifi) without incurring excessive charges would be a huge benefit.


Edit:
Just found the answer to the SMS question.... apparently SMS does work.

 

Thanks for the reply. I currently use a voip app when on wifi too which is good but I'd much prefer integration into the OS.

I know you can send iMessages over wifi but I'm just trying to check you can send SMS messages too.

I'm specifically talking about the new Wifi Calling functionality in IOS8. http://gizmodo.com/what-is-wi-fi-calling-1635271129

I think this is a greatly under appreciated feature and would make things considerably cheaper and easier when roaming - if the networks allow it