Note 4 dying quicker? Dies at 40%?

[AC Question]

Hello there!! My phone is the Samsung Galaxy Note 4 N910A Version 5.1.1
I recently noticed with my phone that it would die at 20%-40% or sometimes when I put on my camera at around those percents... I've also been noticing that its been draining more when its been locked when not a lot of apps are on..
I don't know if its an version bug or something?
I also cannot update to marshmallow since I switched from AT&T to T-Mobile (Traitor!!!!!!) and since it scans through AT&T servers (that I'm not part of anymore) I can't tell if the update is out yet or is not.

I'm really hoping someone has answers, I really don't have the money to get a new contract with a new phone, Please help.. .

 

[nahoku]

If the battery in your phone is the original one, then it's probably just time for a new battery. Do yourself a favor and don't buy a cheap battery. You can purchase Anker's on Amazon, or if you don't mind spending a little more, the AC store has Samsung OEM batteries on sale for $15.95 today.

As far as updating your phone, try to visit an AT&T store and ask them (politely) to upgrade it to Marshmallow, or visit a BestBuy and see if they can do it for you.