AT:

• the upgrade jar reads the elasticsearch port from the configuration
• by default the configuration has the default elasticsearch http port
• the property is added to the environment-config.yaml
• the property is documented in the installation guide and the configuration section of the technical-guide

Context:
In the back-end we are using the java client which needs to use a different port then then the http client port we are using during in the upgrade jar. Eventually we will move to the http client of Elasticsearch anyway when the client supports the whole Elasticsearch API.