Setting up Docker 17.03 CE on Ubuntu 16.04

I’m trying to set up ShinyProxy on an Ubuntu VBox machine. Ubuntu is 16.04. Following https://shinyproxy.io/getting-started/ everything goes fine, up to but not including the step where I try and change the port (Docker startup section) with the line

ExecStart=/usr/bin/docker daemon -H fd:// -D -H tcp://0.0.0.0:2375

results in a message

-bash: /usr/bin/daemon: no such file or directory

Tried to replace the ‘/usr/bin/docker daemon’ with a suitable call to dockerd (as ‘docker daemon’ seems to be deprecated between the time of writing the page i was following and Docker 17.X), but couldn’t find out what the correct options are. Anyone had the same problem, and found a solution?