How do I update my iPhone 6s to iOS 15?

Please try this: Select Settings > General > Software Update. If your iPhone is eligible for an upgrade, you will be promoted to do so. If this does not work for you, let us know exactly what happens. If there is an error message, we need to know what this is also.

Use a computer or the Software Update function in Settings. If you encounter a specific issue, describe it in this thread.

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