IOS 15.8.6 on Iphone 6S Plus. Incredibly unexpected battery drain.

hello everyone, ios 15.8.6 is draining my battery ( 4 months old) as never made, can't understand the policy to block and killing softly the old devices as my trusty beloved iphone 6s plus, the last with the audio jack reason why i still use it. Until the previous update battery duration was incredibly high standing all day. Why a relaise if processor is not in line with it? Another fixing update is coming? Many thanks

iPhone 6s Plus, iOS 15

Posted on Feb 2, 2026 5:35 AM

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Posted on Feb 2, 2026 10:28 PM

Was the battery replaced 4 months ago by Apple? If so, take it back for free diagnostics. The update did very little, except to extend the certificate to use iMessage and FaceTime after 2027 where the previous certificate was set to expire. There were no security patches or features added in the update that would have changed any operations.


If the battery was not replaced by Apple or Service Provider designated by Apple, then you got an aftermarket battery and are going to have very little options.

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Question marked as Top-ranking reply

Feb 2, 2026 10:28 PM in response to yellow amarillo

Was the battery replaced 4 months ago by Apple? If so, take it back for free diagnostics. The update did very little, except to extend the certificate to use iMessage and FaceTime after 2027 where the previous certificate was set to expire. There were no security patches or features added in the update that would have changed any operations.


If the battery was not replaced by Apple or Service Provider designated by Apple, then you got an aftermarket battery and are going to have very little options.

IOS 15.8.6 on Iphone 6S Plus. Incredibly unexpected battery drain.

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