How can I use Jami on Android 4.4?

Some older versions may be?

Hi, yes. The minimum required Android version for Jami was increased to Android 5 nearly three years ago. And because of the fast pace of development, improvements, and bug fixes in Jami, it’s unfortunately not a good idea at all to run that old of a Jami version. I haven’t worked on the Android client much, but I’d imagine that assumptions about the minimum version of Android 5 being available is by now all over the code base, and would probably be quite hard – if not impossible – to port it to older Android versions. As such, I don’t see any easy/feasible way to use Jami on Android versions below 5.