Update iPhone to second newest iOS version

I have an iPhone XR which currently is running iOS 13.7. I would like to update it to iOS 14 but I only have the option to update it to iOS 15. I can't find a siged iOS 14 image anyvhewe (e.g. at ipsw.me). Does anyone have a solution for this issue?

Update iPhone to second newest iOS version
 
 
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