Why does ionic v2 es6 prod app fail to install?

I have built an app using es6 so I can use async/await. The debug version of the app works but when I run the command to build a production version:

ionic build --prod --release

The app builds and when I try to install it the install it, it fails to install but the debug version installs and works fine. Whats the problem here?

In order to install a release build you have to sign the package and zipalign it .

please refer this link for how to sign and zipalign it

This worked but I used Typescript 2.2.0 targeting es5.