It's an Android Lint warning that tells that you should consider updating targetSdkVersion to the latest API level (19 as of now). It's because your target SDK level is lower than your build SDK (defined in project.properties on Eclipse/ADT-based tooling).

It's an Android Lint warning that tells that you should consider updating `targetSdkVersion` to the latest API level (19 as of now). It's because your target SDK level is lower than your build SDK (defined in project.properties on Eclipse/ADT-based tooling).
When you run an app with a given target SDK version on a device actually running a higher API level, the platform enables certain backward-compatibility features. Instead you should ensure that your app works correctly without these features. The comptatibility modes are listed in the [javadoc][1].

[1]: http://developer.android.com/reference/android/os/Build.VERSION_CODES.html