Which Android version was codenamed 'Froyo'?

Android 2.2 was codenamed Froyo, short for “frozen yogurt.”

Froyo was released in May 2010 as Android 2.2, bringing a substantial performance and feature update to the young mobile operating system. It introduced a faster version of Android’s Dalvik runtime through the JIT compiler, improved Exchange support, added support for installing some applications on external storage, and enabled Wi-Fi hotspot and USB tethering features on compatible devices.

The name continued Android’s dessert-themed naming tradition. Froyo followed Eclair, used for Android 2.0 and 2.1, and preceded Gingerbread, which identified Android 2.3. Google used the dessert names publicly for many years, although later releases increasingly emphasized only their numeric versions in consumer branding.

The most precise historical description is that Froyo covered the Android 2.2 release family, including maintenance updates such as 2.2.1, 2.2.2, and 2.2.3. It is easy to confuse Froyo with Gingerbread because both were early Android releases, but 2.3—not 2.2—was Gingerbread.