update from iso 11

Never mind. Misread the question.

Yes you can update all the way to iOS 15.

See here: link-> Update your iPhone, iPad, or iPod touch - Apple Support

Welcome, dano124, to Apple Support Communities!

An iPhone 6s should be able to be updated/upgraded all the way to iOS 15.

If your iPhone is only an iPhone 6 (no s), then it cannot be upgraded past iOS 12.5.5.

Yes.

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