I'd like to thank Opera for keeping Opera Mini updated on Android 5. Android 5 isn't as outdated as you might think: My 2017 Fire tablet has Android 5, and will get security updates until at least 2024. Yet few browsers are updated on Android 5 anymore, I'm glad Opera Mini's one of them.
However, it's dangerous that plain Opera is available on the Android 5 Google Play store despite no longer receiving security updates! Vivaldi, Edge, and Brave, which are no longer updated on Android 5, do not show in the Android 5 app store. I strongly urge the Opera company to remove plain Opera from the Android 5 app store. Alliteratively: Program plain Opera to warn Android 5 users of the security risks, and recommend switching to Opera Mini.