The CloudStack version 4.12.0.0 is a 4.12 non-LTS release, adding multiple features for those who want to access a fresh CloudStack prior to the next LTS. The release 4.12.0.0 combines 12 months of work and adds +200 commits.
Release notes: http://docs.cloudstack.apache.org/en/4.12.0.0/releasenotes
Installation docs: http://docs.cloudstack.apache.org/en/4.12.0.0/installguide
Admin docs: http://docs.cloudstack.apache.org/en/4.12.0.0/adminguide
API docs: http://cloudstack.apache.org/api/apidocs-4.12