 - The app now asks to become the default SMS app when importing or wiping messages
 
 - The app now runs, with most functionality available, on API level 19 (KitKat / 4.4) or later, although message import and scheduled message export still require API level 23 (Marshmallow / 6.0) or later

 - Improved logging (particularly in debug builds)

 - Smaller APK size (of release builds, due to R8 shrinking)

 - Updated Gradle configuration and dependencies

