The Android version codenamed “Ice Cream Sandwich” was Android 4.0.
Released in 2011, Ice Cream Sandwich unified Google’s previously separate phone and tablet interfaces. It followed Android 2.3 Gingerbread on phones and Android 3.0 Honeycomb on tablets, bringing the two branches together in one release. The first phone to ship with it was Samsung’s Galaxy Nexus.
Android 4.0 introduced Google’s Holo visual design, the Roboto typeface, resizable widgets, improved notifications, Face Unlock, NFC sharing through Android Beam, and built-in controls for monitoring mobile-data use. These features make it more than just a dessert-themed codename: it marked a major redesign of Android’s interface and platform strategy.
A common mix-up is confusing it with Android 4.1 Jelly Bean, which came next, or Android 3.0 Honeycomb, the tablet-only release that influenced its design. Ice Cream Sandwich covered versions 4.0 through 4.0.4.