Apollo Client 3.11 introduces several features and improvements, including enhanced subscription APIs with the ability to access `subscribeToMore` in Suspense-enabled hooks, a new `ignoreResults` option for `useSubscription`, and a `restart` function that reconnects subscriptions when called. The release also adds official support for React 19 release candidate versions with improved React Compiler compatibility. New Apollo Client Devtools options are available, including the ability to inspect and monitor multiple client instances and add a custom name to client instances. Additionally, the experimental schema testing utilities have been deprecated in favor of the new `@apollo/graphql-testing-library` package. Potentially breaking fixes include updates to the GraphQL error types and changes to how `nextFetchPolicy` is called.