i’m using iphone se which is same as iphone 6 and recently i feel my battery drain quite fast. only use the phone about 2 yrs or less i think. last time it can tahan about 1 day before charge now i already charge 2 times today.

is it something wrong? it has ask me update to new version ios for sometime but i didn’t. is that the cause that i should update to make the battery more stable?