A quick update,
Ensuring our developers always have access to the latest version of Neo4j is critical for our team so all newly created AuraDB Free instances are Neo4j 5.
We published a post with more details a few days ago, on the improvements 5 brings.
If you have an AuraDB Free instance created before Monday the 24th October, delete it and create another to get a Neo4j 5 version AuraDB Free instance.
Aura Product Management