Created a pull request for this feature. I made upgrades where I could, though it wasn't too easy to test since there aren't any for this plugin.
The biggest issue in this upgrade was leaving the jenkins.version at 1.480 instead of upgrading to 1.580.1 to grab some security fixes. In between the two versions, a core class picked up a new interface requiring role checking. Since I'm not entirely sure where ChannelTransport runs (master or agent) and didn't have a good way of checking my choice, I just decided to leave it.
All feedback is welcome.
This plugin relies on an older version of Jenkins, 1.480. I've been testing migrating to 1.580.1 to grab SECURITY-144, but there are some fundamental changes between versions. Because this plugin has been pretty much functionally untouched since 2014 (findbugs and maven dependency bumps) and it's popularity is rising meteorically, it might be worth keeping the jenkins.version at 1.480.