IMPORTANT: This app has been discontinued on 29.07.2021 and will be replaced by GlowFlutter
GLOW Android is the (currently only german version) of the GLOW App (Giving Light to Our World - glowonline.org) found under: https://play.google.com/store/apps/details?id=com.techlung.android.glow
It is designed to support multiple languages and an automatic update of tracts (without updating the app in playstore) in future.