I need to show a message to update the app if any updated version is in the playstore… How to get the code to Know that the app is updated or not?
To my knowledge there is no offical way to check for updates on the playstore.
You’d have to implement that with your own backend.
Maybe you should take a look at Ionic deploy, then you will be able to update the app automaticely. http://docs.ionic.io/docs/deploy-from-scratch