Click the Deluge icon --> Edit --> Advanced View (Top right corner)
In the repository line put "binhex/arch-deluge:2.0.4.dev38_g23a48dd01-2-01"
Or any other tag/version (replace after the colon) from https://hub.docker.com/r/binhex/arch-deluge/tags?page=1&ordering=last_updated
It's just the one I called works for me.