From the documentation here:
android:targetSdkVersion
An integer designating the API Level that the
application targets. If not set, the default value equals that given
to minSdkVersion. This attribute informs the system that you have
tested against the target version and the system should not enable any
compatibility behaviors to maintain your app's forward-compatibility
with the target version. The application is still able to run on older
versions (down to minSdkVersion).
As Android evolves with each new version, some behaviors and even
appearances might change. However, if the API level of the platform is
higher than the version declared by your app's targetSdkVersion, the
system may enable compatibility behaviors to ensure that your app
continues to work the way you expect. You can disable such
compatibility behaviors by specifying targetSdkVersion to match the
API level of the platform on which it's running. For example, setting
this value to "11" or higher allows the system to apply a new default
theme (Holo) to your app when running on Android 3.0 or higher and
also disables screen compatibility mode when running on larger screens
(because support for API level 11 implicitly supports larger screens).
There are many compatibility behaviors that the system may enable
based on the value you set for this attribute. Several of these
behaviors are described by the corresponding platform versions in the
Build.VERSION_CODES reference.
To maintain your application along with each Android release, you should increase the value of this attribute to match the latest API
level, then thoroughly test your application on the corresponding
platform version. Introduced in: API Level 4
Try increasing the targetSDK attribute to "17" for example.