SchoolTool 2.8 is a development series with a first release in April 2014.
See SchoolTool 2.8 And Beyond for plans regarding this and future releases.
Currently there are only daily builds from trunk branches of actively developed projects, automatically landing in the trunk PPA.
First release featuring the new relationships.
SchoolTool 2.8 And Beyond
SchoolTool 2.6 Release Notes