Why are stock apps different on different carriers?

[GadgetMomma]

First, I'd like to say, please forgive me, and tell me to delete this post if I've done the wrong thing by posting here. I have a question about texting on my s4 (AT&T), and am not sure where exactly to post. In the general forum, carrier specific (if so, which one?)' or the software forum? I originally posted this in the software forum thinking that the reason for the difference was different os versions (4.2.1 vs 4.2.2 for example), but have since found out that both phones are running 4.2.2. So please forgive me, because I usually would never post in two different forums, I just wasn't sure which forum would grab the most responses.

Here is my original post:

I have a Galaxy s4 running 4.2.2 on AT&T. A friend of mine has an S4 running 4.2.2 on Verizon. She has this feature in her stock texting app where if she is sending a group text, she has the option to hit a tab at the bottom of her window and send an individual message to someone in the thread. My stock app doesn't have that, and unless I'm missing something completely obvious, I see no place to turn that feature on. Is that something that is just on verizon? I know carriers usually add their own "stamp" to phones on top of all the other things already on there, but I didn't realize something like that would be different. I thought it was usually differences in fonts, quick toggles, etc. Any thoughts or suggestions are appreciated!

 

[Darnell0216]

The only time everything is untouched is when the phone is straight from Google or someone manages to get a "vanilla" or untouched version of the OS onto the phone, usually by rooting. Once the OS hits the carrier, all bets are off. Logos, tricks, features, and other things are all added or removed by the carrier. Some reasons for any of these changes include compatibility with their own software, network, something requested or that won't be missed, or a battery hog.