With 3.4.0, the default template only supports iOS 6.0 and up. I know that plugins can specify iOS support (apple-ios key in engines tag) but we haven't done it yet. I'm not even sure if the cli plugin installer checks for this yet.
Should we start using this in core plugins? A specific case is this PR: https://github.com/apache/cordova-plugin-camera/pull/24 It is using [ALAssetsLibrary authorizationStatus] and that API only occurs in iOS 6.0 and up. Wrapping this in a runtime os version check is not hard, however (IsAtLeastVersion macro).