hi
i tried uncomment the following line in platforms\android\project.properties

To enable ProGuard to shrink and obfuscate your code, uncomment this (available properties: sdk.dir, user.home):

proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt

and new a file proguard-project.txt in the same folder, then:
ionic build android --release

but looks do not work.
any idea?