But that's something they ought to have explained better from Day 1 of the software change; most users would never expect that swapping a battery could impact a phone's speed.
The fallout over Apple's throttling of older iPhones is continuing as Republican lawmakers sent a letter on Friday to the tech giant demanding answers to more than a dozen questions.
"Lithium-ion batteries become less capable of supplying peak current demands when in cold conditions, (when they) have a low battery charge or as they age over time, which can result in the device unexpectedly shutting down to protect its electronic components", the company said.
Apple acknowledged last month that it was throttling some iPhones to prevent them from turning off prematurely due to weakened batteries.
The disclosure to which Cook apparently was referring was the release notes of the operating system update in question, which Apple released early previous year.
Eight lawsuits have been filed against the company in the USA, over this matter.
On December 20, Apple asserted that iOS slowed down some with battery issues.
The firm said it would reduce the price of an out-of-warranty battery replacement from $79 to $29 for anyone with an iPhone 6.
That disclosure made consumers believe that Apple intentionally slows down old models so that customers can buy new iPhone models. "Maybe we should have been clearer as well, and so we deeply apologize for anybody that thinks we had some kind of other motivation".
Cook also discussed Apple's announcement Wednesday that it is paying $38 billion on its overseas cash and plans to hire 20,000 workers and open a new campus. Let us know in the comments!