Merge release branch '4.7' into master

* 4.7:
  Debian changelog updated
  Implement upgrade path 4.7.0 -> 4.7.1
  Updating pom.xml version numbers for release 4.7.1-SNAPSHOT
  Implement upgrade path 4.6.2 -> 4.6.3
  Updating pom.xml version numbers for release 4.6.3-SNAPSHOT

Author: remibergsma