Emojipedia displaying new emoji flags on Android 5.0 Lollipop
Introduced as part of Unicode 6.0, all flags are implemented using the two-letter regional indicators as listed in ISO_3166-1. As such, systems that do not yet support these characters will simply display the two country code letters, instead of an emoji flag.
iOS displaying regional indicator letters for Denmark
Android 4.4 displaying regional indicator letters for Denmark
Android 5.0 displaying the Flag of Denmark emoji
This brings the total number of country flags available in Android to 219, compared to 10 that are supported on iOS, OS X, Windows, and older versions of Android.
Emojipedia lists the two sets of flags separately, as only the original 10 flags are widely supported at this time.