This release moves our templates forward by adopting the YAML standard for the files. When the new version of the server encounters the old-style text-based templates, a warning is issued advising that these templates should be upgraded. To upgrade, just pass the --upgrade-templates flag and the server will automatically upgrade your templates in place.
For more details on the new template format, see https://github.com/menpo/landmarker.io/wiki/Templates-specification