diff --git a/build.gradle b/build.gradle
index 220f6f3daf5ac..f42c5ad910ee1 100644
--- a/build.gradle
+++ b/build.gradle
@@ -231,7 +231,7 @@ String bwc_tests_disabled_issue = ""
 
 /* there's no existing MacOS release, therefore disable bcw tests */
 if (Os.isFamily(Os.FAMILY_MAC)) {
-  bwc_tests_enabled = false
+//  bwc_tests_enabled = false
   bwc_tests_disabled_issue = "https://github.com/opensearch-project/OpenSearch/issues/4173"
 }
 
diff --git a/qa/mixed-cluster/build.gradle b/qa/mixed-cluster/build.gradle
index 90aeb8faadf80..4f898f79bc898 100644
--- a/qa/mixed-cluster/build.gradle
+++ b/qa/mixed-cluster/build.gradle
@@ -55,6 +55,7 @@ for (Version bwcVersion : BuildParams.bwcVersions.wireCompatible) {
   }
 
   String baseName = "v${bwcVersion}"
+  String segRepCluster = "${baseName}segrep"
 
   /* This project runs the core REST tests against a 4 node cluster where two of
      the nodes has a different minor.  */
@@ -65,6 +66,12 @@ for (Version bwcVersion : BuildParams.bwcVersions.wireCompatible) {
 
       setting 'path.repo', "${buildDir}/cluster/shared/repo/${baseName}"
     }
+
+    "$segRepCluster" {
+      versions = [bwcVersion.toString(), project.version]
+      numberOfNodes = 2
+      setting 'path.repo', "${buildDir}/cluster/shared/repo/${segRepCluster}"
+    }
   }
 
   tasks.register("${baseName}#mixedClusterTest", StandaloneRestIntegTestTask) {
@@ -89,7 +96,26 @@ for (Version bwcVersion : BuildParams.bwcVersions.wireCompatible) {
     onlyIf { project.bwc_tests_enabled }
   }
 
+  tasks.register("${baseName}#segrepMixedClusterTest", StandaloneRestIntegTestTask) {
+    useCluster testClusters."${segRepCluster}"
+    doFirst {
+      delete("${buildDir}/cluster/shared/repo/${segRepCluster}")
+      // Getting the endpoints causes a wait for the cluster
+      println "Test cluster endpoints are: ${-> testClusters."${segRepCluster}".allHttpSocketURI.join(",")}"
+      println "Upgrading one node to create a mixed cluster"
+      testClusters."${segRepCluster}".nextNodeToNextVersion()
+      // Getting the endpoints causes a wait for the cluster
+      println "Upgrade complete, endpoints are: ${-> testClusters."${segRepCluster}".allHttpSocketURI.join(",")}"
+      nonInputProperties.systemProperty('tests.rest.cluster', "${-> testClusters."${segRepCluster}".allHttpSocketURI.join(",")}")
+      nonInputProperties.systemProperty('tests.clustername', "${-> testClusters."${segRepCluster}".getName()}")
+    }
+    systemProperty 'tests.path.repo', "${buildDir}/cluster/shared/repo/${segRepCluster}"
+    systemProperty 'tests.segrep_enabled', true
+    onlyIf { project.bwc_tests_enabled }
+  }
+
   tasks.register(bwcTaskName(bwcVersion)) {
     dependsOn "${baseName}#mixedClusterTest"
+    dependsOn "${baseName}#segrepMixedClusterTest"
   }
 }
diff --git a/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java
index 2e36a352c75dd..a07c4f750b13f 100644
--- a/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java
+++ b/qa/mixed-cluster/src/test/java/org/opensearch/backwards/IndexingIT.java
@@ -32,6 +32,8 @@
 package org.opensearch.backwards;
 
 import org.apache.hc.core5.http.HttpHost;
+import org.apache.hc.core5.http.ParseException;
+import org.apache.hc.core5.http.io.entity.EntityUtils;
 import org.opensearch.LegacyESVersion;
 import org.opensearch.Version;
 import org.opensearch.client.Request;
@@ -45,6 +47,7 @@
 import org.opensearch.common.xcontent.json.JsonXContent;
 import org.opensearch.common.xcontent.support.XContentMapValues;
 import org.opensearch.index.seqno.SeqNoStats;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.rest.RestStatus;
 import org.opensearch.test.rest.OpenSearchRestTestCase;
 import org.opensearch.test.rest.yaml.ObjectPath;
@@ -63,6 +66,9 @@
 
 public class IndexingIT extends OpenSearchRestTestCase {
 
+    protected static final Boolean SEGREP_ENABLED = Boolean.parseBoolean(System.getProperty("tests.segrep_enabled"));
+
+
     private int indexDocs(String index, final int idStart, final int numDocs) throws IOException {
         for (int i = 0; i < numDocs; i++) {
             final int id = idStart + i;
@@ -98,10 +104,115 @@ private int indexDocWithConcurrentUpdates(String index, final int docId, int nUp
         return nUpdates + 1;
     }
 
+    public void printClusterRouting() throws IOException, ParseException {
+        Request clusterStateRequest = new Request("GET", "_cluster/state/routing_nodes?pretty");
+        String clusterState = EntityUtils.toString(client().performRequest(clusterStateRequest).getEntity()).trim();
+        logger.info("cluster nodes: {}", clusterState);
+    }
+
+    public void printIndexSettings(String index) throws IOException, ParseException {
+        Request indexSettings = new Request("GET", index + "/_settings?pretty");
+        String idxSettings = EntityUtils.toString(client().performRequest(indexSettings).getEntity()).trim();
+        logger.info("idxSettings : {}", idxSettings);
+    }
+
+    /**
+     * This test verifies that segment replication does not break when primary shards are on higher version.
+     *
+     * @throws Exception
+     */
+    public void testIndexingWithPrimaryOnBwcNodes() throws Exception {
+        if (SEGREP_ENABLED == false) return;
+        Nodes nodes = buildNodeAndVersions();
+        assumeFalse("new nodes is empty", nodes.getNewNodes().isEmpty());
+        logger.info("cluster discovered:\n {}", nodes.toString());
+        final List<String> bwcNamesList = nodes.getBWCNodes().stream().map(Node::getNodeName).collect(Collectors.toList());
+        logger.info("--> bwc nodes {}", bwcNamesList);
+        final String bwcNames = bwcNamesList.stream().collect(Collectors.joining(","));
+        // Exclude bwc nodes from allocation so that primaries gets allocated on current version
+        Settings.Builder settings = Settings.builder()
+            .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+            .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put("index.routing.allocation.include._name", bwcNames);
+        final String index = "test-index";
+        createIndex(index, settings.build());
+        ensureYellow(index);
+        printClusterRouting();
+
+        printIndexSettings(index);
+
+        int docCount = 200;
+        try (RestClient nodeClient = buildClient(restClientSettings(),
+            nodes.values().stream().map(Node::getPublishAddress).toArray(HttpHost[]::new))) {
+
+            logger.info("allowing replica shards assignment on bwc nodes");
+            updateIndexSettings(index, Settings.builder().putNull("index.routing.allocation.include._name"));
+            printClusterRouting();
+            printIndexSettings(index);
+            ensureGreen(index);
+
+            // Index docs
+            indexDocs(index, 0, docCount);
+
+            // perform a refresh
+            assertOK(client().performRequest(new Request("POST", index + "/_flush")));
+
+            // verify replica catch up with primary
+            assertSeqNoOnShards(index, nodes, docCount, nodeClient);
+        }
+    }
+
+
+    /**
+     * This test creates a cluster with primary on older version. But, replicas
+     *
+     * @throws Exception
+     */
+    public void testIndexingWithReplicaOnBwcNodes() throws Exception {
+        if (SEGREP_ENABLED == false) return;
+        Nodes nodes = buildNodeAndVersions();
+        assumeFalse("new nodes is empty", nodes.getNewNodes().isEmpty());
+        logger.info("cluster discovered:\n {}", nodes.toString());
+        final List<String> bwcNamesList = nodes.getBWCNodes().stream().map(Node::getNodeName).collect(Collectors.toList());
+        logger.info("--> bwc nodes {}", bwcNamesList);
+        final String bwcNames = bwcNamesList.stream().collect(Collectors.joining(","));
+        // Exclude bwc nodes from allocation so that primaries gets allocated on current version
+        Settings.Builder settings = Settings.builder()
+            .put(IndexMetadata.INDEX_NUMBER_OF_SHARDS_SETTING.getKey(), 1)
+            .put(IndexMetadata.INDEX_NUMBER_OF_REPLICAS_SETTING.getKey(), 1)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .put("index.routing.allocation.exclude._name", bwcNames);
+        final String index = "test-index";
+        createIndex(index, settings.build());
+        ensureYellow(index);
+        printClusterRouting();
+        printIndexSettings(index);
+
+        int docCount = 200;
+        try (RestClient nodeClient = buildClient(restClientSettings(),
+            nodes.values().stream().map(Node::getPublishAddress).toArray(HttpHost[]::new))) {
+
+            logger.info("allowing replica shards assignment on bwc nodes");
+            updateIndexSettings(index, Settings.builder().putNull("index.routing.allocation.exclude._name"));
+            printClusterRouting();
+
+            // Index docs
+            indexDocs(index, 0, docCount);
+
+            // perform a refresh
+            assertOK(client().performRequest(new Request("POST", index + "/_flush")));
+
+            // verify replica catch up with primary
+            assertSeqNoOnShards(index, nodes, docCount, nodeClient);
+        }
+    }
+
     public void testIndexVersionPropagation() throws Exception {
         Nodes nodes = buildNodeAndVersions();
         assumeFalse("new nodes is empty", nodes.getNewNodes().isEmpty());
         logger.info("cluster discovered: {}", nodes.toString());
+        logger.info("--> Nodes {}", nodes);
         final List<String> bwcNamesList = nodes.getBWCNodes().stream().map(Node::getNodeName).collect(Collectors.toList());
         final String bwcNames = bwcNamesList.stream().collect(Collectors.joining(","));
         Settings.Builder settings = Settings.builder()
diff --git a/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java b/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
index a5d2e6793f397..11df944f1644a 100644
--- a/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
+++ b/test/framework/src/main/java/org/opensearch/test/rest/OpenSearchRestTestCase.java
@@ -918,6 +918,20 @@ public static void ensureGreen(String index) throws IOException {
         });
     }
 
+    /**
+     * Checks that the specific index is yellow.
+     *
+     * @param index index to test for
+     **/
+    public static void ensureYellow(String index) throws IOException {
+        ensureHealth(index, (request) -> {
+            request.addParameter("wait_for_status", "yellow");
+            request.addParameter("wait_for_no_relocating_shards", "true");
+            request.addParameter("timeout", "70s");
+            request.addParameter("level", "shards");
+        });
+    }
+
     protected static void ensureHealth(Consumer<Request> requestConsumer) throws IOException {
         ensureHealth("", requestConsumer);
     }