For some software developers, a change in the OS user interface is a problem. They are using a development tool that draws controls itself rather than going the extra mile required to use native controls. Native controls are drawn by the OS, not the application. When the app is moved from one OS to another (for example between iOS 6 and iOS 7 or between Windows XP and Windows 7), it takes on the native user interface because it's using native controls. Apps made with development tools that draw their own controls suddenly look out of place and strange.
This is why Real Studio has always used native controls ever since it was introduced in 1998. We want our user's applications to have a user interface that matches the OS. Most iOS development tools don't make the effort to use native controls. We do. We previewed our iOS development efforts at our annual user conference last week. We use all native controls for iOS because that's the level of effort our users have come to expect from us.