When a new IPhone is scheduled to come out in about 3 to 6 months, they intentionally push software updates to the soon to be not newest model of IPhone that screw up the software governing how the battery is smart charged to make the total battery life degrade rather quickly, and also just generally slow down many of the processes on the phone as well: now that the battery is degraded, the hardware does not actual get the volts and amps from it needed for optimized, speedy processing.
Up until they were rather publically outed for doing this, they lied to everyone on their support forums and in stores claiming it either wasnt happening or was due to something wrong the user did.
Nothing like gaslighting your entire customer base!
Hilariously though, because these are IPhone users we are talking about (you know, generally defineable as allergic to learning anything technical, extremely susceptible to overproduced advertisements, vain, etc), it didnt really make a huge dent in overall market share.
So yeah, they say they dont do this /anymore/ but you can find threads on reddit and such with people reporting that it still goes on. Having worked for various tech firms I can tell you its possible they are still doing it but just in a more clever, harder to prove way, but I dont use Apple products so I dont care to launch my own singlehanded investigation into proving if they are /still/ doing it.