Nope. iOS 6 adds auto layout to Interface Builder and Core Layout to the runtime. You'll either start at the largest resolution and setup constraints as the screen size shrinks or at the smallest resolution and do the opposite.
ldpi: low-density screens (~120dpi)
mdpi: medium-density (~160dpi) [baseline]
hdpi: high-density (~240dpi)
xhdpi: extra high-density (~320dpi)
there are also screen size qualifiers, small, normal, large, extra large.
AFAIK, the density qualifiers are still being used, and are mentioned in the "new" design guidelines document as well, giving me the impression they may stick around for a while. http://developer.android.com/design/style/devices-displays.h...