Subscribe to hardware backbutton on android does not work anymore

Ionic Framework
2

my ionic info:

Ionic:

ionic (Ionic CLI) : 4.12.0
Ionic Framework : @ionic/angular 4.6.2
@angular-devkit/build-angular : 0.13.9
@angular-devkit/schematics : 7.2.4
@angular/cli : 7.3.9
@ionic/angular-toolkit : 1.4.1

Cordova:

cordova (Cordova CLI) : 9.0.0 (cordova-lib@9.0.1)
Cordova Platforms : android 8.0.0
Cordova Plugins : cordova-plugin-ionic-keyboard 2.1.3, cordova-plugin-ionic-webview 3.1.2, (and 15 other plugins)

System:

NodeJS : v10.15.3 (C:\Program Files\nodejs\node.exe)
npm : 6.4.1
OS : Windows 10