Earlier this year after Debian decided to adopt systemd in favor of Upstart or other alternatives, Ubuntu pledged to support systemd after long favoring their "own" Upstart init system. The official plan for the Ubuntu Upstart to systemd migration is to become the default before Ubuntu 16.04 LTS but beyond that their systemd plans are still quite fluid.
While systemd will not replace Upstart in Ubuntu 14.10 if the support isn't ready before October, there's already a systemd package for Ubuntu Utopic so developers and early adopters can begin testing. A systemd package just landed in Utopic that's in better shape than a systemd package found in utopic-proposed from a few days ago.
Canonical's Martin Pitt wrote on his blog, "I think systemd in current utopic works well enough to not break a developer’s day to day workflow, so we can now start parallelizing the work of identifying packages which only have upstart jobs and provide corresponding systemd units (or SysV script). Also, this hasn’t yet been tested on the phone at all, I’m sure that it’ll require quite some work (e. g. lxc-android-config has a lot of upstart jobs). To clarify, there is nofixed date/plan/deadline when this will be done, in particular it might well last more than one release cycle. So we’ll “release” (i. e. switch to it as a default) when it’s ready :-)"