Apple just published a letter to customers apologizing for the “misunderstanding” around older iPhones being slowed down, following its recent admission that it was, in fact, slowing down older phones in order to compensate for degrading batteries. “We know that some of you feel Apple has let you down,” says the company. “We apologize.”

Apple says in its letter that batteries are “consumable components,” and is offering anyone with an iPhone 6 or later a battery replacement for $29 starting in late January through December 2018 — a discount of $50 from the usual replacement cost. Apple’s also promising to add features to iOS that provide more information about the battery health in early 2018, so that users are aware of when their batteries are no longer capable of supporting maximum phone performance. This is a significant change in attitude around iPhone batteries — a decade ago, when the first iPhone came out, Apple said most iPhone users would never need to replace their batteries.

iOS will offer more information about battery health in early 2018

iPhone owners have long believed Apple artificially slows down older phones to drive new sales. But the new information from Apple about performance management poured gasoline on that long-simmering frustration, leading to a lot of bad press and multiple lawsuits. What made it all seem worse is that the scope of the performance penalty only came to light after being discovered by a developer instead of being clearly disclosed by Apple.

The iPhone 6, 6S, SE, and 7 have much slower peak performance as they get older and their batteries aren’t able to provide as much power to the processor. Apple had actually announced this change to performance along with iOS 10.2.1 a year ago, as the fix to a problem with the iPhone 6 that caused unexpected shutdowns if older batteries couldn’t provide enough power to the processor. But it wasn’t transparent about the performance penalty, and the new benchmarks suggest the penalty is much more significant than previously believed.

“This feature’s only intent is to prevent unexpected shutdowns”

For its part, Apple continues to insist that it’s never artificially slowed down phones — just that it’s aggressively managing phone performance to maximize the lifespan of iPhone batteries. “This feature’s only intent is to prevent unexpected shutdowns so that the iPhone can still be used,” according to a new knowledge base article Apple published alongside today’s letter. “This power management works by looking at a combination of the device temperature, battery state of charge, and the battery’s impedance. Only if these variables require it, iOS will dynamically manage the maximum performance of some system components, such as the CPU and GPU in order to prevent unexpected shutdowns.”

Processor speed is just one piece of the battery- and performance-management puzzle, according to Apple: iPhones with older batteries may also more aggressively dim their screens, have lower maximum speaker volumes, and even have their camera flashes disabled when the system needs more peak power than the battery can provide. But other core features, like the cell radio, GPS, and camera quality, aren’t affected, Apple says. The whole approach actually quite clever, but cleverness isn’t a great substitute for speed.

Apple has a long way to go rebuilding trust with its customers

In any event, Apple has a long way to go rebuilding trust with its customers — this story broke well past the tech press and hit TV morning shows and local news with zero nuance about “smoothing instantaneous peaks” and battery chemistry degradation. A lot of people already believed that Apple slowed down their iPhones, and this wave of news was a big data point confirming that for them. It’s going to be a difficult road back.

In its letter, Apple says “we’ve always wanted our customers to be able to use their iPhones as long as possible.” If Apple is serious about that, and equally serious about the battery being a consumable, these first two steps are just the beginning of a major reset in the way we think about maintaining the most important devices in our lives.