Block6 App
Block6 is an SMS app that makes it easy to block numbers. It provides a simple interface with few options, and no ads, in contrast to many of the other SMS apps available.Block6 is intended mainly for phones running Android versions less than 7.0. It targets Android version 4.4 KitKat (API Level 19) and above. It also works fine on Android 9 Pie.
Android 7.0 introduced better built-in support for blocking numbers so this app is probably less useful on versions 7+.
Block6 is free and open source on Github at https://github.com/travistynes/block6. Feel free to send feedback, pull requests, or use the code for your own purpose.
