[ionic v4.0.0]: App hangs at white screen just after splash screen

I upgrade my project from ionic v4 beta to ionic v4.0.0 stable. Now i am trying to run my app in android 5.0 device it hangs on white screen just after splash.

Here is my ionic info:

Ionic:

   ionic (Ionic CLI)             : 4.10.2 (/usr/local/lib/node_modules/ionic)
   Ionic Framework               : @ionic/angular 4.0.0
   @angular-devkit/build-angular : 0.12.4
   @angular-devkit/schematics    : 7.2.4
   @angular/cli                  : 7.2.4
   @ionic/angular-toolkit        : 1.3.0

Cordova:

   cordova (Cordova CLI) : 8.1.2 (cordova-lib@8.1.1)
   Cordova Platforms     : android 7.1.4
   Cordova Plugins       : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 2.3.3, (and 10 other plugins)

System:

   Android SDK Tools : 26.1.1 (/Users/hsain/Library/Android/sdk)
   NodeJS            : v10.11.0 (/usr/local/Cellar/node/10.11.0/bin/node)
   npm               : 6.7.0
   OS                : macOS Mojave
   Xcode             : Xcode 10.1 Build version 10B61

I am getting the key viewport-fit is not recognized and ignored. android error.

even on ionic 4 it says minimum API version is 22 (Android 5.1), it only work on API version 24 (Android 7.0).
your android 5.0 is not works now, but I hope ionic team can make backward compatible to API 21

i have an emulator running android 7.0 but i got the same problem