AppCompat v21 builds themes that require the new APIs provided in API 21 (Android 5.0). To compile your application with AppCompat, you must also compile against API 21. The recommended setup for compiling/building with API 21 is a compileSdkVersion
of 21
and a buildToolsVersion
of 21.0.1
(which is the highest at this time – you always want to use the latest build tools).