I might be wrong, but I read here far too many cases in which Apple broke something during the battery replacement and had to hand out a phone replacement.
Now, I don't know if it is due to the nature of forums in which people tend to share issues more predominantly, so I'm exponentially exaggerating or Apple really does screw up a lot of replacements.
I'm asking because if I ever replace the battery on my iPhone 6s, I can't have them giving me a new one - mine is on iOS 9, and I obviously cannot force them to downgrade one for me - and it obviously wouldn't be the same if they gave me a new one in whichever version the newest is at that point.
Now, I don't know if it is due to the nature of forums in which people tend to share issues more predominantly, so I'm exponentially exaggerating or Apple really does screw up a lot of replacements.
I'm asking because if I ever replace the battery on my iPhone 6s, I can't have them giving me a new one - mine is on iOS 9, and I obviously cannot force them to downgrade one for me - and it obviously wouldn't be the same if they gave me a new one in whichever version the newest is at that point.