What's the meaning of "App must be built for iOS devices with Retina display"

Question

Apple announced that recently: 'Starting May 1, new apps and app updates submitted to the App Store must be built for iOS devices with Retina display and iPhone apps must also support the 4-inch display on iPhone 5'.

I wonder what's the meaning of "App must be built for iOS devices with Retina display"?

Is there some apps can not run on retina devices? Or it means the graphics must be design for retina devices?

If someone submitted an app with OpenGL only for 320*480 devices(3GS), and scales it on retina devices, will it be rejected?

Answer 1

It means that your app must look nice on retina devices (with higher resolution) and iPhone 5 (with larger screen).

They want to guarantee every user the best possible experience with the application they download / buy.

If the scaling results in a crappy look, it will likely be rejected. If it doesn't look crappy… well, it's the App Store, so you never know… it may still be rejected for not following the rules. Unless you become famous, that is.

Pulitzer Prize Winning cartoons

In December 2009, Apple banned a cartoon app called NewsToons by cartoonist Mark Fiore, on the grounds that it "ridiculed public figures."[29][30] In April 2010, Fiore won the Pulitzer prize for his political satire cartoons, making history as the very first internet-only cartoonist to win the prestigious journalistic prize.[29][30][31] Following public outcry after the story broke in the wake of the award, Apple asked Fiore to resubmit his app, and it was subsequently accepted. Fiore said, "Sure, mine might get approved, but what about someone who hasn’t won a Pulitzer and who is maybe making a better political app than mine? Do you need some media frenzy to get an app approved that has political material?"[30]

Source: Wikipedia