Then the title of the entire thread is wrong correct? Yet how does a hardware issue "start" with a software change? ii.e.: "The problem started after installing iOS 6, so the issue has been around long before iOS 7." I'd suggest that a problem that starts after a software change is, more than likely, related to that software change....
"Every product that Apple comes out with is met with industry scorn."
The first iPod was completely scorned: as there'd been mp3 players for a decade.
And yes, the first iPhone was practically laughed off as a complete joke. "no keyboard?"
"Nearly one year" means it's near the end of the warranty: best to get it looked at right away as a failure to hold a charge in that short a time is an indication something is wrong: either the charger or cable (try another one of each?) or the unit itself. Does it charge and hold a charge when connected to the computer he syncs it to? If so then the charger is bad.
No crashes so far (127 apps here) on my 5s, the background update should make getting the updated compatible versions widely distributed rather painless.
Oh and iOS 7? Even on my 5 it's performance was superior to 6 so there's that.
Probably the best route, a phone that old has accumulated a bunch of dustbunnies in the code that can use cleaning out. Every update etc. is an opportuninty for just some slight nicks. And the nicks add up: especially if using an anti-virus program such as Symantecs....
"The iPhone 5s and 5c were grantedregulatory approval to appear on China Mobile's nascent 4G TD-LTE network in September," So the product is finished and has been approved. I expect they're adjusting to a faster customer (carrier) response loop for new products stationing someone right there.
Saw the battery savings with my own eyes: first full charge to drain was over 10.5 hours of usage making a substantial improvement to my 5. A nice surprise.
Currently at 7 hrs 11 minutes standby, 1 hr 33 minutes use and 78% remaining battery.