@Test void usageOfDeprecatedFeatures() {
    WebClient webClient = WebClient.builder(elasticsearch().baseUrl()).factory(ClientFactory.builder()
      .useHttp2Preface(false).build()).build();
    final AggregatedHttpResponse response =
      webClient.execute(HttpRequest.of(RequestHeaders.of(HttpMethod.GET,
        "/_migration/deprecations"))).aggregate().join();
    String responseBody = response.contentAscii();
    if (!responseBody.equals("""
      {"cluster_settings":[],"node_settings":[],"index_settings":{},"ml_settings":[],"ccr_auto_followed_system_indices":[]}""")) {
      LOGGER.warn("The ElasticSearch instance used during IT's is using deprecated features or "
        + "configuration. This is likely nothing to be really worried about (for example 'xpack.monitoring.enabled' "
        + "setting), but nevertheless it should be looked at to see if our docker image used during "
        + "integration tests needs updating for the next version of ElasticSearch. "
        + "See https://www.elastic.co/guide/en/elasticsearch/reference/current/migration-api-deprecation.html "
        + "for more information. This is the deprecation warning we received:\n\n"
        + response.contentAscii());
    }
  }
The current implementation does not include dependency aggregation. It includes retrieval of
pre-aggregated links, usually made via zipkin-dependencies
zipkin-storage/elasticsearch/src/test/java/zipkin2/elasticsearch/integration/ITElasticsearchStorage.java