If i update my att samsung galaxy s6 edge plus, will it lock?

[AC Question]

No one was able to help me so far.
I bought a used samaung galaxy s6 edge plus last week, its almost brand new and i noticed it still had android 5.1.1 and i want to update it to marshmallow or nougat.
So, i went to use iphone for a while until someone stole my iphone 6s, blah blah, long story, im back with android.
The las android phone i used was an s4 and when i updated to the latest version i couldnt use my sim because it got locked, thats why i switched to apple.
Anyways, since this is a att phone and im using movistar i have no issues right now, but i want to update it, do you guys know if my phone would be lock again?
If theres a solution do you guys mind telling me what to do?
Also, since i dont have a att sim i cant download the update from settings.

 

[Tim1954]

Software updates can (should) be done on WiFi. No sim required.
Updating software shouldn't affect sim or network things, not sure what happened there. Settings do "slip" sometimes and you may have to go through and make sure everything is as you want it.