NEW YORK (CBSNewYork) - It's not your imagination.
Apple confirmed the company does indeed slow down older iPhones as they age.
But they say it is for a good reason.
The lithium-ion batteries in older devices can't keep up with peak demand for power, Apple says.
The batteries may need to be serviced or recycled, according to the company.
Virtually all functions other than making phone calls may slow down as the device ages, reported CBS News' Anna Werner.
After older batteries struggled to keep up with iPhone 6s, the company released an update and offered limited battery replacements. Apple now admits that update slowed the phones down.
"Our goal is to deliver the best experience for customers, which includes overall performance and prolonging the life of their devices," Apple said in a statement to CBS This Morning.
That explanation is not sitting well with some.
A California man has filed a class action suit, saying that Apple's action to slow down phones happened without users consent. The lawsuit alleges breach of implied contract "by purposefully slowing down older iPhone models when new models come out and by failing to properly disclose that at the time that the parties entered into an agreement."
EXTRA: Read The Lawsuit
By late Thursday night, a second class action suit had been filed in Illinois.
It all started with a post on Reddit. Someone complained their iPhone 6S was operating slowly, but returned to normal once a new battery was installed.
Computer scientist John Poole decided to test the theory. He posted on his Geekbench blog that Apple was limiting the power going from the phone's battery to its processor. That processor runs apps and other functions.
"Your web browser will be slower, instant messaging will be slower, your camera will be slower," Poole said.
He says the only fix is to replace the battery.
"They've been ratcheting it down so that your battery can handle that load," said David Carnoy, with tech website CNET. "It's not necessarily the worst thing in the world and maybe it is helping your phone from completely turning off, but they should tell you that."
Outside the Apple store on the Upper West Side, many customers were outraged by the company's lack of transparency.
"I came here for a battery check," Martin Espinoza, of the Bronx, told CBS2's Alice Gainer. "So the battery is a problem, but that has nothing to do with the system. The system is working fine."
"I think they've been pulling that trick on us for years," another man said.
But most said they weren't upset enough to walk away.
"No, not really," one man said.
"No, because I'll probably continue to get the new one, unfortunately," another added.
Except one woman who uses another phone brand.
"I think apples belong in a fruit basket," she said.
If your iPhone is slowing down, replacing the battery is the only permanent solution. If it is no longer under warranty, a new battery costs $79, Werner reported.
Apple has sold more than 1 billion iPhones since they first came to market. It says the iPhone SE, 6, 6S and 7 are all impacted.
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