Why are there no up to date upgrade notes? There are a few changes in 6.x that are important to make it working correctly. They should be mentioned in this document for users to know what changes affect their setup.
Please update this ASAP and keep it updates in future. It looks like noone touched this document in a while.
I know about the changelog, but the changelog is a changelog and should not contain a summary of what config has to be changed. It can link to the upgrade notes.