It is well known that Apple slows older iPhone models. But when is an iPhone an "old model"? After a year? After two? And is each older iPhone slowing down or just those who have been stressed heavily (that's what needs need)?
Apple had intermediate older devices with decreasing battery power to prevent crashing of the device.
Because of course that is not very nice to make the customer to meet this decision as it has really made really problems only with colder temperatures and Apple has not really communicated the whole thing was a modification of the function.
When the device crashes due to an old weak battery, reducing performance to prevent further crashes in the future. Compared to earlier, the user can now simply remove the limitation in the settings.
This is already outdated. Apple did that then around the batterySenior devices to protect. That started at the time of 2 year old devices.
Meanwhile, Apple does not do that because it was neatly on the lid.
Only when the residual capacity of the battery reaches a low level. (Not the state of charge, but the overall condition of the battery)
But you can believe I would have to adjust that anyway nothing is throttled.
When a new one comes out .. , not!