diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java
index 812a572437950..a2ba8dd7f0923 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/MachineLearningIT.java
@@ -232,6 +232,10 @@
 
 public class MachineLearningIT extends ESRestHighLevelClientTestCase {
 
+    private static final RequestOptions POST_DATA_OPTIONS = RequestOptions.DEFAULT.toBuilder()
+        .setWarningsHandler(warnings -> Collections.singletonList("Posting data directly to anomaly detection jobs is deprecated, " +
+            "in a future major version it will be compulsory to use a datafeed").equals(warnings) == false).build();
+
     @After
     public void cleanUp() throws IOException {
         new MlTestStateCleaner(logger, highLevelClient().machineLearning()).clearMlMetadata();
@@ -435,7 +439,8 @@ public void testForecastJob() throws Exception {
             builder.addDoc(hashMap);
         }
         PostDataRequest postDataRequest = new PostDataRequest(jobId, builder);
-        machineLearningClient.postData(postDataRequest, RequestOptions.DEFAULT);
+        // Post data is deprecated, so expect a deprecation warning
+        machineLearningClient.postData(postDataRequest, POST_DATA_OPTIONS);
         machineLearningClient.flushJob(new FlushJobRequest(jobId), RequestOptions.DEFAULT);
 
         ForecastJobRequest request = new ForecastJobRequest(jobId);
@@ -461,7 +466,9 @@ public void testPostData() throws Exception {
         }
         PostDataRequest postDataRequest = new PostDataRequest(jobId, builder);
 
-        PostDataResponse response = execute(postDataRequest, machineLearningClient::postData, machineLearningClient::postDataAsync);
+        // Post data is deprecated, so expect a deprecation warning
+        PostDataResponse response = execute(postDataRequest, machineLearningClient::postData, machineLearningClient::postDataAsync,
+            POST_DATA_OPTIONS);
         assertEquals(10, response.getDataCounts().getInputRecordCount());
         assertEquals(0, response.getDataCounts().getOutOfOrderTimeStampCount());
     }
@@ -1068,7 +1075,8 @@ public void testDeleteForecast() throws Exception {
         }
 
         PostDataRequest postDataRequest = new PostDataRequest(jobId, builder);
-        machineLearningClient.postData(postDataRequest, RequestOptions.DEFAULT);
+        // Post data is deprecated, so expect a deprecation warning
+        machineLearningClient.postData(postDataRequest, POST_DATA_OPTIONS);
         machineLearningClient.flushJob(new FlushJobRequest(jobId), RequestOptions.DEFAULT);
         ForecastJobResponse forecastJobResponse1 = machineLearningClient.forecastJob(new ForecastJobRequest(jobId), RequestOptions.DEFAULT);
         ForecastJobResponse forecastJobResponse2 = machineLearningClient.forecastJob(new ForecastJobRequest(jobId), RequestOptions.DEFAULT);
diff --git a/client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/MlClientDocumentationIT.java b/client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/MlClientDocumentationIT.java
index 209a483fe0c1d..749290a16501b 100644
--- a/client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/MlClientDocumentationIT.java
+++ b/client/rest-high-level/src/test/java/org/elasticsearch/client/documentation/MlClientDocumentationIT.java
@@ -251,6 +251,10 @@
 
 public class MlClientDocumentationIT extends ESRestHighLevelClientTestCase {
 
+    private static final RequestOptions POST_DATA_OPTIONS = RequestOptions.DEFAULT.toBuilder()
+        .setWarningsHandler(warnings -> Collections.singletonList("Posting data directly to anomaly detection jobs is deprecated, " +
+            "in a future major version it will be compulsory to use a datafeed").equals(warnings) == false).build();
+
     @After
     public void cleanUp() throws IOException {
         new MlTestStateCleaner(logger, highLevelClient().machineLearning()).clearMlMetadata();
@@ -1382,7 +1386,8 @@ public void testDeleteForecast() throws Exception {
         }
 
         PostDataRequest postDataRequest = new PostDataRequest(job.getId(), builder);
-        client.machineLearning().postData(postDataRequest, RequestOptions.DEFAULT);
+        // Post data is deprecated, so expect a deprecation warning
+        client.machineLearning().postData(postDataRequest, POST_DATA_OPTIONS);
         client.machineLearning().flushJob(new FlushJobRequest(job.getId()), RequestOptions.DEFAULT);
 
         ForecastJobResponse forecastJobResponse = client.machineLearning().
@@ -1519,7 +1524,8 @@ public void testForecastJob() throws Exception {
             builder.addDoc(hashMap);
         }
         PostDataRequest postDataRequest = new PostDataRequest(job.getId(), builder);
-        client.machineLearning().postData(postDataRequest, RequestOptions.DEFAULT);
+        // Post data is deprecated, so expect a deprecation warning
+        client.machineLearning().postData(postDataRequest, POST_DATA_OPTIONS);
         client.machineLearning().flushJob(new FlushJobRequest(job.getId()), RequestOptions.DEFAULT);
 
         {
@@ -1788,9 +1794,14 @@ public void testPostData() throws Exception {
             postDataRequest.setResetEnd(null);
             postDataRequest.setResetStart(null);
 
+            // Post data is deprecated, so expect a deprecation warning
+            PostDataResponse postDataResponse = client.machineLearning().postData(postDataRequest, POST_DATA_OPTIONS);
+            // The end user can use the default options without it being a fatal error (this is only in the test framework)
+            /*
             // tag::post-data-execute
             PostDataResponse postDataResponse = client.machineLearning().postData(postDataRequest, RequestOptions.DEFAULT);
             // end::post-data-execute
+            */
 
             // tag::post-data-response
             DataCounts dataCounts = postDataResponse.getDataCounts(); // <1>
@@ -1822,9 +1833,14 @@ public void onFailure(Exception e) {
             final CountDownLatch latch = new CountDownLatch(1);
             listener = new LatchedActionListener<>(listener, latch);
 
+            // Post data is deprecated, so expect a deprecation warning
+            client.machineLearning().postDataAsync(postDataRequest, POST_DATA_OPTIONS, listener);
+            // The end user can use the default options without it being a fatal error (this is only in the test framework)
+            /*
             // tag::post-data-execute-async
             client.machineLearning().postDataAsync(postDataRequest, RequestOptions.DEFAULT, listener); // <1>
             // end::post-data-execute-async
+            */
 
             assertTrue(latch.await(30L, TimeUnit.SECONDS));
         }
diff --git a/client/rest/src/main/java/org/elasticsearch/client/RequestOptions.java b/client/rest/src/main/java/org/elasticsearch/client/RequestOptions.java
index 6e44c219cd049..3eac76e7a143a 100644
--- a/client/rest/src/main/java/org/elasticsearch/client/RequestOptions.java
+++ b/client/rest/src/main/java/org/elasticsearch/client/RequestOptions.java
@@ -219,8 +219,9 @@ public void setHttpAsyncResponseConsumerFactory(HttpAsyncResponseConsumerFactory
          * fail the request if the warnings returned don't
          * <strong>exactly</strong> match some set.
          */
-        public void setWarningsHandler(WarningsHandler warningsHandler) {
+        public Builder setWarningsHandler(WarningsHandler warningsHandler) {
             this.warningsHandler = warningsHandler;
+            return this;
         }
 
         /**
diff --git a/docs/reference/ml/anomaly-detection/apis/post-data.asciidoc b/docs/reference/ml/anomaly-detection/apis/post-data.asciidoc
index 42b385a515950..4d9bb3fce1474 100644
--- a/docs/reference/ml/anomaly-detection/apis/post-data.asciidoc
+++ b/docs/reference/ml/anomaly-detection/apis/post-data.asciidoc
@@ -6,6 +6,8 @@
 <titleabbrev>Post data to jobs</titleabbrev>
 ++++
 
+deprecated::[7.11.0, "Posting data directly to anomaly detection jobs is deprecated, in a future major version a <<ml-api-datafeed-endpoint,{dfeed}>> will be required."]
+
 Sends data to an anomaly detection job for analysis.
 
 [[ml-post-data-request]]
diff --git a/x-pack/plugin/ml/qa/basic-multi-node/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlBasicMultiNodeIT.java b/x-pack/plugin/ml/qa/basic-multi-node/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlBasicMultiNodeIT.java
index 071b731bd9d59..6ca5d98714728 100644
--- a/x-pack/plugin/ml/qa/basic-multi-node/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlBasicMultiNodeIT.java
+++ b/x-pack/plugin/ml/qa/basic-multi-node/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlBasicMultiNodeIT.java
@@ -8,6 +8,7 @@
 import org.apache.http.entity.ContentType;
 import org.apache.http.nio.entity.NStringEntity;
 import org.elasticsearch.client.Request;
+import org.elasticsearch.client.RequestOptions;
 import org.elasticsearch.client.Response;
 import org.elasticsearch.client.ResponseException;
 import org.elasticsearch.common.Strings;
@@ -15,7 +16,6 @@
 import org.elasticsearch.test.rest.ESRestTestCase;
 import org.yaml.snakeyaml.util.UriEncoder;
 
-import javax.print.attribute.standard.JobStateReason;
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.util.Collections;
@@ -32,6 +32,10 @@ public class MlBasicMultiNodeIT extends ESRestTestCase {
 
     private static final String BASE_PATH = "/_ml/";
 
+    private static final RequestOptions POST_DATA_OPTIONS = RequestOptions.DEFAULT.toBuilder()
+        .setWarningsHandler(warnings -> Collections.singletonList("Posting data directly to anomaly detection jobs is deprecated, " +
+            "in a future major version it will be compulsory to use a datafeed").equals(warnings) == false).build();
+
     public void testMachineLearningInstalled() throws Exception {
         Response response = client().performRequest(new Request("GET", "/_xpack"));
         Map<?, ?> features = (Map<?, ?>) entityAsMap(response).get("features");
@@ -66,6 +70,7 @@ public void testMiniFarequote() throws Exception {
                 "{\"airline\":\"AAL\",\"responsetime\":\"132.2046\",\"sourcetype\":\"farequote\",\"time\":\"1403481600\"}\n" +
                 "{\"airline\":\"JZA\",\"responsetime\":\"990.4628\",\"sourcetype\":\"farequote\",\"time\":\"1403481700\"}",
                 randomFrom(ContentType.APPLICATION_JSON, ContentType.create("application/x-ndjson"))));
+        addData.setOptions(POST_DATA_OPTIONS);
         Response addDataResponse = client().performRequest(addData);
         assertEquals(202, addDataResponse.getStatusLine().getStatusCode());
         Map<String, Object> responseBody = entityAsMap(addDataResponse);
@@ -165,6 +170,8 @@ public void testMiniFarequoteReopen() throws Exception {
                 "{\"airline\":\"KLM\",\"responsetime\":\"1355.4812\",\"sourcetype\":\"farequote\",\"time\":\"1403481900\"}\n" +
                 "{\"airline\":\"NKS\",\"responsetime\":\"9991.3981\",\"sourcetype\":\"farequote\",\"time\":\"1403482000\"}",
                 randomFrom(ContentType.APPLICATION_JSON, ContentType.create("application/x-ndjson"))));
+        // Post data is deprecated, so expect a deprecation warning
+        addDataRequest.setOptions(POST_DATA_OPTIONS);
         Response addDataResponse = client().performRequest(addDataRequest);
         assertEquals(202, addDataResponse.getStatusLine().getStatusCode());
         Map<String, Object> responseBody = entityAsMap(addDataResponse);
@@ -205,6 +212,8 @@ public void testMiniFarequoteReopen() throws Exception {
                 "{\"airline\":\"UAL\",\"responsetime\":\"8.4275\",\"sourcetype\":\"farequote\",\"time\":\"1407081900\"}\n" +
                 "{\"airline\":\"FFT\",\"responsetime\":\"221.8693\",\"sourcetype\":\"farequote\",\"time\":\"1407082000\"}",
                 randomFrom(ContentType.APPLICATION_JSON, ContentType.create("application/x-ndjson"))));
+        // Post data is deprecated, so expect a deprecation warning
+        addDataRequest2.setOptions(POST_DATA_OPTIONS);
         Response addDataResponse2 = client().performRequest(addDataRequest2);
         assertEquals(202, addDataResponse2.getStatusLine().getStatusCode());
         Map<String, Object> responseBody2 = entityAsMap(addDataResponse2);
diff --git a/x-pack/plugin/ml/qa/native-multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlJobIT.java b/x-pack/plugin/ml/qa/native-multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlJobIT.java
index 434037a959308..4252902f110a8 100644
--- a/x-pack/plugin/ml/qa/native-multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlJobIT.java
+++ b/x-pack/plugin/ml/qa/native-multi-node-tests/src/javaRestTest/java/org/elasticsearch/xpack/ml/integration/MlJobIT.java
@@ -28,6 +28,7 @@
 import org.junit.After;
 
 import java.io.IOException;
+import java.util.Collections;
 import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -475,6 +476,10 @@ public void testDeleteJob_TimingStatsDocumentIsDeleted() throws Exception {
         assertThat(entityAsMap(openResponse), hasEntry("opened", true));
 
         Request postDataRequest = new Request("POST", MachineLearning.BASE_PATH + "anomaly_detectors/" + jobId + "/_data");
+        // Post data is deprecated, so expect a deprecation warning
+        postDataRequest.setOptions(RequestOptions.DEFAULT.toBuilder()
+            .setWarningsHandler(warnings -> Collections.singletonList("Posting data directly to anomaly detection jobs is deprecated, " +
+                "in a future major version it will be compulsory to use a datafeed").equals(warnings) == false));
         postDataRequest.setJsonEntity("{ \"airline\":\"LOT\", \"response_time\":100, \"time\":\"2019-07-01 00:00:00Z\" }");
         client().performRequest(postDataRequest);
         postDataRequest.setJsonEntity("{ \"airline\":\"LOT\", \"response_time\":100, \"time\":\"2019-07-01 02:00:00Z\" }");
diff --git a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/rest/job/RestPostDataAction.java b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/rest/job/RestPostDataAction.java
index 01ac45eb4f2b8..dd899ea6e0e91 100644
--- a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/rest/job/RestPostDataAction.java
+++ b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/rest/job/RestPostDataAction.java
@@ -14,6 +14,7 @@
 import org.elasticsearch.xpack.ml.MachineLearning;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
@@ -29,13 +30,13 @@ public List<Route> routes() {
         return Collections.emptyList();
     }
 
-    @Override
-    public List<ReplacedRoute> replacedRoutes() {
-        // TODO: remove deprecated endpoint in 8.0.0
-        return Collections.singletonList(
-            new ReplacedRoute(POST, MachineLearning.BASE_PATH + "anomaly_detectors/{" + Job.ID.getPreferredName() + "}/_data",
-                POST, MachineLearning.PRE_V7_BASE_PATH + "anomaly_detectors/{" + Job.ID.getPreferredName() + "}/_data")
-        );
+    public List<DeprecatedRoute> deprecatedRoutes() {
+        final String msg = "Posting data directly to anomaly detection jobs is deprecated, " +
+            "in a future major version it will be compulsory to use a datafeed";
+        return Arrays.asList(
+            new DeprecatedRoute(POST, MachineLearning.BASE_PATH + "anomaly_detectors/{" + Job.ID.getPreferredName() + "}/_data", msg),
+            new DeprecatedRoute(POST, MachineLearning.PRE_V7_BASE_PATH + "anomaly_detectors/{" + Job.ID.getPreferredName() + "}/_data",
+                msg));
     }
 
     @Override
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/index_layout.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/index_layout.yml
index 64a613bd946d9..5626f541bc2a9 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/index_layout.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/index_layout.yml
@@ -4,6 +4,10 @@ setup:
 ---
 "Test CRUD on two jobs in shared index":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
       ml.put_job:
         job_id: index-layout-job
@@ -58,6 +62,8 @@ setup:
         job_id: index-layout-job2
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: index-layout-job
         body: >
@@ -65,6 +71,8 @@ setup:
           {"airline":"JZA","responsetime":"990.4628","sourcetype":"farequote","time":"1403481700"}
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: index-layout-job2
         body: >
@@ -341,6 +349,10 @@ setup:
 ---
 "Test unrelated index":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
       ml.put_job:
         job_id: index-layout-job
@@ -368,6 +380,8 @@ setup:
         job_id: index-layout-job
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: index-layout-job
         body: >
@@ -649,6 +663,10 @@ setup:
 ---
 "Test force close does not create state":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
       headers:
         Authorization: "Basic eF9wYWNrX3Jlc3RfdXNlcjp4LXBhY2stdGVzdC1wYXNzd29yZA==" # run as x_pack_rest_user, i.e. the test setup superuser
@@ -680,6 +698,8 @@ setup:
         job_id: index-layout-force-close-job
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: index-layout-force-close-job
         body: >
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/job_cat_apis.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/job_cat_apis.yml
index a82ce20032094..25a127f077c24 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/job_cat_apis.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/job_cat_apis.yml
@@ -72,7 +72,13 @@ setup:
 ---
 "Test cat anomaly detector jobs":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: job-stats-test
         body: >
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_crud.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_crud.yml
index ec7528098db72..0be490fe79a49 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_crud.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_crud.yml
@@ -657,7 +657,9 @@
 ---
 "Test close job":
   - skip:
-      features: headers
+      features:
+        - "headers"
+        - "warnings"
   - do:
       ml.put_job:
         job_id: jobs-crud-close-job
@@ -682,6 +684,8 @@
         job_id: jobs-crud-close-job
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: jobs-crud-close-job
         body: >
@@ -915,7 +919,9 @@
 ---
 "Test force close job":
   - skip:
-      features: headers
+      features:
+        - "headers"
+        - "warnings"
   - do:
       ml.put_job:
         job_id: jobs-crud-force-close-job
@@ -943,6 +949,8 @@
         job_id: jobs-crud-force-close-job
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: jobs-crud-force-close-job
         body: >
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_get_stats.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_get_stats.yml
index 4313d48f0e146..8910fdca0c918 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_get_stats.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/jobs_get_stats.yml
@@ -72,7 +72,13 @@ setup:
 ---
 "Test get job stats after uploading data prompting the creation of some stats":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: job-stats-test
         body: >
@@ -110,7 +116,13 @@ setup:
 ---
 "Test get job stats for closed job":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: job-stats-test
         body: >
@@ -341,7 +353,13 @@ setup:
 ---
 "Test no exception on get job stats with missing index":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: job-stats-test
         body: >
diff --git a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/post_data.yml b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/post_data.yml
index 6cba27ae8dc6c..e19a8c48a042f 100644
--- a/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/post_data.yml
+++ b/x-pack/plugin/src/test/resources/rest-api-spec/test/ml/post_data.yml
@@ -46,7 +46,13 @@ setup:
 
 ---
 "Test POST data job api, flush, close and verify DataCounts doc":
+  - skip:
+      features:
+        - "warnings"
+
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: post-data-job
         body:
@@ -123,7 +129,13 @@ setup:
 ---
 "Test flush with skip_time":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: post-data-job
         body:
@@ -146,6 +158,8 @@ setup:
 
   # Send some data that should be ignored
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: post-data-job
         body:
@@ -160,6 +174,8 @@ setup:
 
   # Send data that will create results for the bucket after the skipped one
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: post-data-job
         body:
@@ -191,8 +207,12 @@ setup:
   - skip:
       reason: "https://github.com/elastic/elasticsearch/issues/34747"
       version: "6.5.0 - "
+      features:
+        - "warnings"
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       catch: missing
       ml.post_data:
         job_id: not_a_job
@@ -207,6 +227,8 @@ setup:
             time: 1403481700
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       catch: /parse_exception/
       ml.post_data:
         job_id: post-data-job
@@ -222,6 +244,8 @@ setup:
             time: 1403481700
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       catch: /parse_exception/
       ml.post_data:
         job_id: post-data-job
@@ -280,12 +304,18 @@ setup:
 ---
 "Test flushing and posting a closed job":
 
+  - skip:
+      features:
+        - "warnings"
+
   - do:
       catch: /status_exception/
       ml.flush_job:
         job_id: post-data-closed-job
 
   - do:
+      warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       catch: /status_exception/
       ml.post_data:
         job_id: post-data-closed-job
diff --git a/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlJobSnapshotUpgradeIT.java b/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlJobSnapshotUpgradeIT.java
index 7a25007efd7ac..740e529264bb3 100644
--- a/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlJobSnapshotUpgradeIT.java
+++ b/x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/MlJobSnapshotUpgradeIT.java
@@ -248,7 +248,19 @@ protected OpenJobResponse openJob(String jobId) throws IOException {
     }
 
     protected PostDataResponse postData(String jobId, String data) throws IOException {
-        return hlrc.postData(new PostDataRequest(jobId, XContentType.JSON, new BytesArray(data)), RequestOptions.DEFAULT);
+        // Post data is deprecated, so a deprecation warning is possible (depending on the old version)
+        RequestOptions postDataOptions = RequestOptions.DEFAULT.toBuilder()
+            .setWarningsHandler(warnings -> {
+                if (warnings.isEmpty()) {
+                    // No warning is OK - it means we hit an old node where post data is not deprecated
+                    return false;
+                } else if (warnings.size() > 1) {
+                    return true;
+                }
+                return warnings.get(0).equals("Posting data directly to anomaly detection jobs is deprecated, " +
+                    "in a future major version it will be compulsory to use a datafeed") == false;
+            }).build();
+        return hlrc.postData(new PostDataRequest(jobId, XContentType.JSON, new BytesArray(data)), postDataOptions);
     }
 
     protected FlushJobResponse flushJob(String jobId) throws IOException {
diff --git a/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/30_ml_jobs_crud.yml b/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/30_ml_jobs_crud.yml
index 92268391fae21..f840ec80226be 100644
--- a/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/30_ml_jobs_crud.yml
+++ b/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/mixed_cluster/30_ml_jobs_crud.yml
@@ -87,6 +87,10 @@
 
 ---
 "Create a job in the mixed cluster and write some data":
+
+  - skip:
+      features: allowed_warnings
+
   - do:
       ml.put_job:
         job_id: mixed-cluster-job
@@ -113,6 +117,8 @@
         job_id: mixed-cluster-job
 
   - do:
+      allowed_warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: mixed-cluster-job
         body:
diff --git a/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/30_ml_jobs_crud.yml b/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/30_ml_jobs_crud.yml
index eb04ff0bf83f0..3a1618dff100c 100644
--- a/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/30_ml_jobs_crud.yml
+++ b/x-pack/qa/rolling-upgrade/src/test/resources/rest-api-spec/test/old_cluster/30_ml_jobs_crud.yml
@@ -15,6 +15,9 @@ setup:
 ---
 "Put job on the old cluster and post some data":
 
+  - skip:
+      features: allowed_warnings
+
   - do:
       ml.put_job:
         job_id: old-cluster-job
@@ -41,6 +44,8 @@ setup:
         job_id: old-cluster-job
 
   - do:
+      allowed_warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: old-cluster-job
         body:
@@ -73,6 +78,9 @@ setup:
 ---
 "Put categorization job on the old cluster and post some data":
 
+  - skip:
+      features: allowed_warnings
+
   - do:
       ml.put_job:
         job_id: old-cluster-categorization-job
@@ -104,6 +112,8 @@ setup:
         job_id: old-cluster-categorization-job
 
   - do:
+      allowed_warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: old-cluster-categorization-job
         body:
@@ -131,6 +141,10 @@ setup:
 
 ---
 "Put job on the old cluster with the default model memory limit and post some data":
+
+  - skip:
+      features: allowed_warnings
+
   - do:
       ml.put_job:
         job_id: no-model-memory-limit-job
@@ -152,6 +166,8 @@ setup:
         job_id: no-model-memory-limit-job
 
   - do:
+      allowed_warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: no-model-memory-limit-job
         body:
@@ -186,6 +202,9 @@ setup:
 ---
 "Put job with timing stats checking on the old cluster and post some data":
 
+  - skip:
+      features: allowed_warnings
+
   - do:
       ml.put_job:
         job_id: old-cluster-job-with-ts
@@ -212,6 +231,8 @@ setup:
         job_id: old-cluster-job-with-ts
 
   - do:
+      allowed_warnings:
+        - 'Posting data directly to anomaly detection jobs is deprecated, in a future major version it will be compulsory to use a datafeed'
       ml.post_data:
         job_id: old-cluster-job-with-ts
         body: