The Apollo Client Devtools have been improved with a new architecture that addresses stability and performance issues, including fixes for slow responses and broken queries. The dark mode has also been enhanced, and GraphQL subscriptions are now fully supported in GraphiQL. Additionally, client-side schema support has been added, allowing developers to query local state data and view the schema for their local state. The Devtools will no longer support Apollo Client 1.0, but an old version is available for manual installation. Future updates include official support for more browsers, sophisticated schema exploration, and time traveling debugging.