in google play store there is no update options

Question

There is a problem in App update in my application, When there is new version upload in Google play store and when i redirect to Google play store for version update at that time there is no option for version update, there is still two options displayed uninstall or open.I have develop below code for version update.

try {
 startActivity(new Intent(Intent.ACTION_VIEW,Uri.parse("market://details?id="+PACKAGE_NAME)));
}
catch (android.content.ActivityNotFoundException anfe) {
startActivity(new Intent(Intent.ACTION_VIEW,Uri.parse("http://play.google.com/store/apps/details?id="+PACKAGE_NAME)));
}