Comment 14 for bug 1287147

1.18.0 supports
New and Notable with 1.18.0
    https://launchpad.net/juju-core/+milestone/1.18.0

* Support for proxies
* Managing authorised ssh keys
* Backup and restore the state-server (bootstrap node)
* Run arbitrary commands on some or all instances
* Use metadata generate-tools instead of sync-tools to generated
  simple streams metadata
* The bootstrap --source option was replaced with --metadata-source
* Timeouts for bootstrap are configurable for environments
* Bootstrapping the local provider for lxc no longer requires sudo
* Juju local provider can use clone for faster LXC
* Juju now supports juju-mongodb, a mongodb tuned for juju’s needs
* The "null" provider is now called "manual" in the juju config.
* The destroy-environment command requires the environment name
* Juju unset-env
* Juju retry-provisioning
* Bash completions include flags, machines, services, and units

Also...It supports:
* Joyent Cloud.
    It is not a secret, but it is not announced until we write some beautiful documentation.
    Note that juju 1.17.7 has no support for Joyent.
* Charms define default series
    Charms can define the series they support and which is default. This permits a single charm
    to support 12.04, 14.04, and 16.04.