Angela Lang/CNET

Apple's $29 battery replacement program may have seriously dinged sales of its 2018 iPhone models.

The company replaced 11 million iPhone batteries under the program, John Gruber of tech-focused blog Daring Fireball reported Monday, citing Apple CEO Tim Cook at an all-hands meeting.

Typically, the company replaces 1 million to 2 million batteries each year, Daring Fireball noted.

Cook cited the program's negative impact on Apple's revenue in a Jan. 2 sales warning to investors but didn't offer specific numbers.

However, if at least five times the usual number of Apple customers replaced their iPhone's battery for $29 instead of splashing out for the $749 XR, the $999 XS or the $1,099 XS Max, that's a lot of lost revenue.

Apple decided to offer the cheaper battery replacements as an apology after users learned in 2017 that Apple had been slowing down older iPhones to prevent unexpected shutdowns related to old batteries.

Apple didn't immediately respond a request for comment.

On Monday, iPhone chipmaker Dialog said its preliminary revenue for the fourth quarter landed at the low end of its target. Last week, Apple reportedly cut its iPhone production for the first quarter by 10 percent and slashed iPhone prices in China.

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