I don't think so - I think it's more that Apple are strongly pushing developers to support iOS 7 only for newer apps. Apple are now suggesting developers should

I don't think so - I think it's more that Apple are strongly pushing developers to support iOS 7 only for newer apps. Apple are now suggesting developers should be using auto layout by default (which in iOS 7 saves considerable time), but until now the toolset for working with auto layout was woefully inadequate (...some might say it still is). It's a lot easier to sell supporting iOS 7 only if all the users who haven't - or can't - upgrade can since have access to older versions of your apps.