4.3.1 did not work on OSX 10.11.6 as reported above. Scrolling down on
the downloads page there is a "Previous DisplayLink Software Releases" section. Picked 4.1.11 from there, installed it, and the monitor works - it buzzes loudly, but the display functions work correctly.
I'll try 2.5.1 next & see whether that fixes the buzzing problem.