Hello, I'm surprised that udevil still has the systemd unit installed in the wrong place, because it should have been addressed by the fix for bug #782875 Mateusz, I'm not sure what the problem is, the debian/rules file looks correct in sid.
Linking the unit file works though, I suspect your problem is that you didn't realize that this is a unit _template_. A unit for a specific user is started by systemctl start devmon@username.service The devmon@.service unit itself cannot be started by design. This is documented in /usr/share/doc/udevil/README.gz in the "POST INSTALL" section. Mateusz, could you please also backport the eventual systemd installation fix to Jessie? Either in backports or as a bugfix release in the main archive. As this would simply fix a bug without compromising functionality (no units will be started automatically), I think it can simply go into the main archive and backports are not necessary. Kind regards, Ondřej Grover