For all the time and money invested into iPad 2 accessories, it turns out that some may not work for those who buy the new iPad. MacWorld said those upgrading should make sure their accessories are compatible with the new version.

"The new iPad is exactly the same height and width as the iPad 2, but ever so slightly – 0.03 inches, to be exact – thicker," the website said. "The lens for the new iPad's improved camera is also a fraction of an inch bigger. But the second- and third-generation iPads are otherwise physically identical – all the buttons, switches, jacks and ports are even in the same locations. The two models are also electrically and mechanically identical insofar as accessories are concerned."

MacWorld said Apple's keyboard dock, most iPad stands and mounts and bags and protective sleeves "shouldn't be a problem" with the new iPad, but said to be careful with folio cases, shells and keyboard cases carrying over from the iPad 2 to the new iPad.

MacNN said that some of the magnetic sensors in the new iPad may have been changed as well, so some third-party iPad cases may not work as well with the new version of Apple's tablet.