I was able to make my app work on Android v. 4.4.2, replacing the cordova-plugin-ionic-webview version 2, with version 1.2.1
The commands I used where these:
cordova plugin rm cordova-plugin-ionic-webview
cordova plugin add cordova-plugin-ionic-webview@1.2.1
ionic cordova platforms remove android
rm -rf plugins
ionic cordova build android