How do I update iOS 12.5.6 to a later version on an iPhone 6s

One thing that you should know and confirm and that is whether you have an iPhone 6s or do you have an iPhone 6 (Without the S) This is important because an iPhone 6 can only be updated up to iOS 12.5.6 and NOTHING HIGHER. You need an iPhone 6s to update higher than that to iOS 15/16. Double check which iPhone you have.

Open Settings ➔ General ➔ About ➔ Model Name: What does it state there?

Axel F.

If the developer of the app has removed the older version of the app that worked with iOS 12.5.6 then there is no way to download that previous version from the App Store.

Quick Google search on Spotify informed me that Spotify requires iOS 13 or higher to download and operate on an iPhone.

Axel F.