The release is available in binary (http://uk1.maven.org/maven2/org/openengsb/openengsb-root/31/openengsb-root-31.pom), source (https://github.com/openengsb/openengsb-root/zipball/v31) and Maven:
<parent>
<groupId>org.openengsb</groupId>
<artifactId>openengsb-root</artifactId>
<version>31</version>
</parent>
There are 11 resolved issues included in this release, as such we've documented them on the v31 release notes page:
http://openengsb.org/index/download/openengsb-root/v31.html
Enjoy!
-The OpenEngSB team.