On Thursday, the company posted a lengthy message on its website.
In-depth explanation of controversial updates.
To make up for this, Apple will temporarily reduce the price of the replacement battery for the iPhone 6 to $29 from the end of January.
Prices will return to the usual $79 in 2019.
Customers are unhappy with the company's software updates that deliberately slow down older phones in some cases to extend battery life.
Some people think this is a strategy to upgrade people to new devices.
Many have filed a lawsuit against the feature and are seeking a status of class action.
The feature will remain on the phone, but Apple says the upcoming iOS update will "give users a clearer picture of the health of the iPhone battery ".
"It doesn't say if it will give them the ability to turn off or turn on features.
"We know that some people feel that Apple has disappointed you.
"We apologize," said the message.
The company confirmed the slowdown last week, but said it was part of a power management function designed to prevent the old battery from suddenly turning off.
"First of all, we never-
And never.
To deliberately shorten the life of any Apple product, or reduce the user experience to drive the customer to upgrade and do anything, "the Post said.
Related information: If you think Apple slowed down your phone a year ago, some iPhone users reported that their device was accidentally turned off even if they had some battery left.
According to Apple, this is not caused by a battery defect, but a normal problem with the aging of lithium-ion batteries.
To fix this, Apple included an update in iOS that will slow down the phone during peak handling events to prevent the battery from turning off.
It affects iPhone 6, iPhone 6 Plus, iPhone 6 S Plus, and iPhone SE.
Apple then launched the same update for iPhone 7 and iPhone 7 Plus devices.
It didn't tell the customer how the update worked at the time.
Apple said that when iOS 11 was released this fall, users' performance began to slow down.
The company said it first assumed it was caused by a "normal, temporary" lag caused by the new OS update and a small error in iOS.
"We now believe that another reason for these user experiences is the continued chemical aging of batteries in older iPhone 6 and iPhone 6 s devices," the company said . ".
Apple called its lithium-ion batteries "consumables" in the post, meaning they should be replaced.
But due to the design of the iPhone, the process is not as simple as using a new battery.
To replace the battery on your iPhone, you have to go to the Apple retailer or ship your phone to Apple.
You can also use the third one.
Although these options will cancel the existing warranty, the party service or ordering kit is done on its own.
Apple says upgrading to a new battery will eliminate any slowdown associated with the update.