Joplin's v3.1.6 APK includes an armeabi-v7a folder, which should contain the 32-bit builds of native code:

Notes/follow-up questions:

  • The minSdkVersion for Joplin 3.1.6 is 23. This corresponds to Android 6.0.
  • Where are you installing Joplin from?
  • What error message are you getting?