AppEngine: Get current serving application version

String version = SystemProperty.version.get();
String applicationVersion = SystemProperty.applicationVersion.get();

This is the syntax:

public static final SystemProperty applicationVersion

The major version number for the currently running version of the application plus a timestamp at which it was deployed. Has the key, "com.google.appengine.application.version".

See here

PS. One puzzle still remains. What does timestamp next to version means and how to read it??

EDIT: Here is the key to the mystery.

 Date UploadDate = new Date(Long.parseLong(
   applicationVersion.substring(applicationVersion.lastIndexOf(‌​".")+1))
   / (2 << 27) * 1000);

For Python (GAE SDK release: "1.4.2")

version_id = self.request.environ["CURRENT_VERSION_ID"].split('.')[1]

timestamp = long(version_id) / pow(2,28) 

version = datetime.datetime.fromtimestamp(timestamp).strftime("%d/%m/%y %X")

See http://groups.google.com/group/google-appengine-python/browse_thread/thread/f86010e7cf3c71b4

os.environ['CURRENT_VERSION_ID']