Xcode 6 includes new iOS Simulator features that allow developers to resize the simulated screen for any arbitrary resolution. 9to5Mac first reported this was imminent in May.
Although the feature is very temperamental in the first beta, it clearly leads the way to a future with a much more diverse lineup of screen resolutions. This allows developers to test for future iOS devices that do not exist today — such as 4.7 inch and 5.5 inch iPhones for example.
9to5Mac also reported that Apple was working on iPhones with screens featuring resolutions of 1704×960. This new ‘multi resolution’ feature should help developers prepare for the future, even without Apple explicitly acknowledging new form factors are in the works.