upstart vs systemd on 16.04

I’m try to wrap my head around what’s going on with the startup scripts since the Jetpack 2.3 release moved Ubuntu to 16.04. It appears that Ubuntu is now using systemd to handle startup services, stored on the TX1 in /lib/systemd/system/. However, all of the old upstart scripts are still also packaged on the device in /etc/init/ – I tried adding an upstart script, but got some errors that upstart wasn’t running, so that tipped me off that these must just be leftover from 14.04. Can anyone confirm whether the new package has fully ported to systemd for startup services?

The init stuff is purely from Ubuntu, so their documentation on changes going from 14.04 LTS to 16.04 LTS should be accurate. So far as I can tell very few Linux distributions go purely to systemd without some legacy part left behind (this might just be in compatibility packaging already served by systemd, or it might be some part not yet adapted to systemd). I couldn’t say for sure which parts are or are not systemd at this time.