DigiKam 5 is out now and I'm looking forward to upgrade it on my systems. Here's the announcement on their blog:
https://www.digikam.org/node/755
Image by Caulier Gilles (
https://www.flickr.com/photos/digikam/), CC-BY
Among a lot of improvements they also got rid of the big KDE dependencies so all the quirks when using it on any other desktop should be gone.