K-9 Mail targets Java 1.6. The current development version of K-9 Mail runs on Android 4.0.3 (API level 15) and newer versions.
Install the following via the Android SDK Manager:
If you want to modify K-9 Mail we highly recommend using Android Studio. You need at least version 1.0.0.
Use the "Import project" functionality of Android Studio to start the import wizard. Then select K-9 Mail's
settings.gradle file from the project root. The rest should happen automatically.
To create a debug build on Unix-based systems use the command:
On Windows open the command prompt and enter the command: