Changed rate plan, got new iOS features.

[APX7000]

iPhone 6, unlocked, JB, iOS 9.0.2

Gave up my unlimited data plan - too expensive!

Went to 2gig roll over, unlimited txt and phone.

Once I changed my phone plan, I got 2 new features;
Wifi calling
Free wifi hotspot

With unlimited data plan, if I tried to activate the wifi hotspot, a message popped up saying to upgrade my plan ($20/mo) to use hotspot.

Then I noticed the wifi calling option magically appeared in the settings.

Did AT&T push a cellular update to my iPhone? That's the only way I can see, especially wifi calling from appearing.

 

[Skull One]

They pushed a very small update to your iPhone thru a system very similar to the PRL (Preferred Roaming List) system. It is a "Contract" level piece of data that allows a carrier to turn on/off certain features of the iPhone. This ability was created by the cellular companies long before the first iPhone was made.

 

[APX7000]

I know carriers push updates whether you want it or not. Twice in 4 years I noticed my iPhone screen come on and announced a carrier update l or something like that was taken place. No option to reject the upgrade.

One update I noticed added severe WX alerts as well as AMBER alerts.

 

[bear7962]

I also have AT&T and still have the unlimited Data plan. I have both wifi calling and wifi assist. The option came with one of the IOS updates within the last 8 months and when they began to work depended on your geographic area. One required you to enable it, the other just started to show as active.