Moderator Notice
@FaithA - I enhanced your thread title, and moved your thread to the Devices sub-forum.
Hopefully this will attract the attention of someone with knowledge of using Kobo Arc and/or the calibre server.
When you say it 'stopped working several updates ago'. are you referring to calibre or the Kobo device software updates? And might it have stopped working when calibre's version number changed from 2.xx to 3.xx ?
BR