How can I update my iPhone 6s Plus to iOS 16.6

Yup. I had an iPhone 6S for several years and I replaced it last year (2024). No OS updates for at least a year.

Edited to add: Actually there were OS updates until the end (fall of 2024); however, the updates weren't the same as what the newer phones were getting.

iOS 15.8.3 is the end of the update road for the iPhone 6s Plus.

If you want to run iOS 16, you will need an iPhone 8, iPhone 8 Plus or iPhone X.

But, since you will be shopping for a new phone, it would make more sense to look for a model that will run a current iOS 18 version. My recommendation would be an iPhone 15 Plus or higher model to run AI.

An iPhone 6s, iPhone 6s Plus, iPhone 7, iPhone 7 Plus, or iPhone SE 1 isn't capable of 16 or above; they require an A11 or better CPU.

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