You can have a read here: https://support.apple.com/en-ca/HT201222 https://support.apple.com/en-ca/HT201222 Basically apple does not release security updates a

You can have a read here: https://support.apple.com/en-ca/HT201222 https://support.apple.com/en-ca/HT201222 Basically apple does not release security updates after a major version unless it's a really extreme case. I was in the same position and need to support several iOS apps and upgrade them to iOS13. I don't like buying new technology so I purchased a refurbished iPhone 8 with a new battery and screen.