https://motherboard.vice.com/en_us/article/j5kd7x/iphone-slow-planned-obsolescence-ios-12-wwdc

The most exciting thing about Apple’s WWDC keynote wasn’t about new hardware, it was about old iPhones. Apple vowed Monday that the new iOS will not break old iPhones and will in fact make them faster, directly addressing the planned obsolescence conspiracy theory.

The theory goes something like this: tech companies sell hardware that is designed to break, generally aligned with the release of a new product, so that you have to buy something new on a set time schedule.