Systemd 205 is a very big release so let's cut straight to the release announcement:
Let this one be known as the "dynamic" release, where things became dynamic! Or call it the "cgroups" release, where we took possession of the cgroup tree!
This release introduces a number of major new concepts, such as transient units, scopes and slices, which turn systemd into something that is far more dynamic than it ever was (this is primarily made visible in the new "systemd-run" tool, which I invite you to play around with). With this release the systemd binary now does *all* cgroup management (be it as the host's PID1, a session manager, or the PID 1 of a container), and logind and nspawn simply defer their cgroup work. All objects showing up in the cgroup tree are now objects managed by systemd itself. The APIs for this are not documented yet, but will be soon. This brings our systemd userspace much closer to the unified single-writer cgroup hierarchy that Tejun has being working towards from the kernel side.
There's two new unit types, a concept of transient units, logind updates, a new mini-daemon, cgroup changes, a new bus, the systemd-run tool, and much more to the systemd 205 release.