As of June 2021, with the release of Neo4j 4.3.0 halin is now deprecated.
The software will continue to be available as a GraphApp and via the URL above; and if you currently depend on it, it will not break or disappear. Halin will not support all 4.3.0 features, and you may encounter incompatibilities when using Halin with this version. Halin will continue to support 3.5 <= Neo4j <= 4.2 as it always did.