Android 2.2

Android 2.2 was released on May 20, 2010, it uses the codename "Froyo" which is short for frozen yogurt.

Android 2.2.1
Android 2.2.1 was an update to Android 2.2, it had various bug fixes, performance improvements, and security updates.

Android 2.2.2
Android 2.2.2 was an update to Android 2.2.1, it had minor bug fixes.

Android 2.2.3
Android 2.2.3 was an update to Android 2.2.2, it had two security updates.

Screenshots
These screenshots are from Android x86 2.2.1