Rui Carmo
This has been blowing up in the media over the past few days, and is hardly unsurprising either way you look at it, especially because it was unstated common knowledge in the underground repair “community”–which was rampant in my neck of the woods for years given the continued absence of an official Apple retail store and the gaps that needed filling.
As an added data point, I replaced my iPhone 6 battery back in August because it was failing around the 30% mark, and the performance increase was very noticeable indeed–right until iOS 11 came along, that is.
Even if 11.2 is now almost fast enough on this hardware, if I hadn’t replaced the battery the phone would likely be completely unusable by now.