discount on mobile android?

Do I get a discount on android version of ntrack? I’ve been an ntrack user for years and upgraded several times.

I take that as a no.

You can get the Android version of n-Track from Google Play. There currently are discounts to get the Android or iOS versions for existing desktop users, it would be difficult given the way the app stores work.
However when you purchase n-Track on an Android device you can later install it on any other Android device. The same applies for iOS. I.e. you can purchase once and use the app on your phone and tablet (given that the phone and tablet both use Android or both use iOS).