This is the first formal baseline release of the device tree specification. This document is a first iteration of ePAPR 1.1 and picks up where it left off in 2012.
The next release, v1.0 is planned for the end of August, 2016, which will be up to date with current core DT bindings used by the Linux kernel.
A second major release is planned for December 2016 to cover new features. The timeline for planned future releases are shown here and you can always find the latest release, as well as all older releases, in our GitHub repository: Devicetree Specification release repository