Is it possible to use transparency in an iPhone app icon?

Question

I created a 57×57 circular icon (without shine) which has transparency outside of the circle for my app. I can successfully install the app on Simulator and iPhone. It works fi

Answer 1

When trying to prepare an app update in iTunes Connect today I uploaded a 1 layer 1024x1024 PNG in RGB 8bits/channel color mode. I got an error message stating:

"Images can’t contain alpha channels or transparencies.":

That's the rule for the App Store as recently as 2015/01/22. I'm including a screenshot.