Get the installer of Zelená pošta 3.0 that is free and have a look at users' reviews on Droid Informer. The app is developed for Android 4.0 and higher. The download of this application doesn't contain viruses or any kind of malware. Zelena Posta is the creator of Zelená pošta that can be found in the Tools category.
The latest update was on Feb 28, 2017 and the app was downloaded and set up by over 1K users. Google Play shows that this application is rated 3.1 by its users.