diff --git a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
index 2d3206b917e7c..8f2cbeb2984bb 100644
--- a/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
+++ b/server/src/main/java/org/opensearch/action/admin/cluster/storedscripts/PutStoredScriptRequest.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.action.admin.cluster.storedscripts;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.common.bytes.BytesReference;
@@ -67,7 +68,11 @@ public PutStoredScriptRequest(StreamInput in) throws IOException {
         super(in);
         id = in.readOptionalString();
         content = in.readBytesReference();
-        mediaType = in.readMediaType();
+        if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
         context = in.readOptionalString();
         source = new StoredScriptSource(in);
     }
@@ -147,7 +152,11 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeOptionalString(id);
         out.writeBytesReference(content);
-        mediaType.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
         out.writeOptionalString(context);
         source.writeTo(out);
     }
diff --git a/server/src/main/java/org/opensearch/action/index/IndexRequest.java b/server/src/main/java/org/opensearch/action/index/IndexRequest.java
index 3ca69a8a868d4..c59125b98e243 100644
--- a/server/src/main/java/org/opensearch/action/index/IndexRequest.java
+++ b/server/src/main/java/org/opensearch/action/index/IndexRequest.java
@@ -56,6 +56,7 @@
 import org.opensearch.common.unit.ByteSizeValue;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.common.xcontent.XContentHelper;
+import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.common.Strings;
 import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -158,7 +159,11 @@ public IndexRequest(@Nullable ShardId shardId, StreamInput in) throws IOExceptio
         isRetry = in.readBoolean();
         autoGeneratedTimestamp = in.readLong();
         if (in.readBoolean()) {
-            contentType = in.readMediaType();
+            if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+                contentType = in.readMediaType();
+            } else {
+                contentType = in.readEnum(XContentType.class);
+            }
         } else {
             contentType = null;
         }
@@ -665,7 +670,11 @@ private void writeBody(StreamOutput out) throws IOException {
         out.writeLong(autoGeneratedTimestamp);
         if (contentType != null) {
             out.writeBoolean(true);
-            contentType.writeTo(out);
+            if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+                contentType.writeTo(out);
+            } else {
+                out.writeEnum((XContentType) contentType);
+            }
         } else {
             out.writeBoolean(false);
         }
diff --git a/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java b/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java
index 993959d2feefb..19f2a1fd90815 100644
--- a/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java
+++ b/server/src/main/java/org/opensearch/action/ingest/PutPipelineRequest.java
@@ -32,11 +32,13 @@
 
 package org.opensearch.action.ingest;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.io.stream.StreamOutput;
+import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -68,7 +70,11 @@ public PutPipelineRequest(StreamInput in) throws IOException {
         super(in);
         id = in.readString();
         source = in.readBytesReference();
-        mediaType = in.readMediaType();
+        if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
     }
 
     PutPipelineRequest() {}
@@ -95,7 +101,11 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeString(id);
         out.writeBytesReference(source);
-        mediaType.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java
index 574e45410f2b2..b63a242902253 100644
--- a/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java
+++ b/server/src/main/java/org/opensearch/action/ingest/SimulatePipelineRequest.java
@@ -32,12 +32,14 @@
 
 package org.opensearch.action.ingest;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequest;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.logging.DeprecationLogger;
+import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.core.xcontent.ToXContentObject;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -83,7 +85,11 @@ public SimulatePipelineRequest(BytesReference source, MediaType mediaType) {
         id = in.readOptionalString();
         verbose = in.readBoolean();
         source = in.readBytesReference();
-        mediaType = in.readMediaType();
+        if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
     }
 
     @Override
@@ -121,7 +127,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalString(id);
         out.writeBoolean(verbose);
         out.writeBytesReference(source);
-        mediaType.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/search/PutSearchPipelineRequest.java b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineRequest.java
index a8a4646c68746..bcfb3ecf61a76 100644
--- a/server/src/main/java/org/opensearch/action/search/PutSearchPipelineRequest.java
+++ b/server/src/main/java/org/opensearch/action/search/PutSearchPipelineRequest.java
@@ -8,6 +8,7 @@
 
 package org.opensearch.action.search;
 
+import org.opensearch.Version;
 import org.opensearch.action.ActionRequestValidationException;
 import org.opensearch.action.support.master.AcknowledgedRequest;
 import org.opensearch.common.bytes.BytesReference;
@@ -46,7 +47,11 @@ public PutSearchPipelineRequest(StreamInput in) throws IOException {
         super(in);
         id = in.readString();
         source = in.readBytesReference();
-        mediaType = in.readMediaType();
+        if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType = in.readMediaType();
+        } else {
+            mediaType = in.readEnum(XContentType.class);
+        }
     }
 
     @Override
@@ -71,7 +76,11 @@ public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         out.writeString(id);
         out.writeBytesReference(source);
-        mediaType.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java
index 1d9f2c643e2ad..0d930544d79e1 100644
--- a/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java
+++ b/server/src/main/java/org/opensearch/action/termvectors/TermVectorsRequest.java
@@ -40,6 +40,7 @@
 import org.opensearch.action.get.MultiGetRequest;
 import org.opensearch.action.support.single.shard.SingleShardRequest;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.ParseField;
 import org.opensearch.common.bytes.BytesArray;
 import org.opensearch.common.bytes.BytesReference;
@@ -185,7 +186,11 @@ public TermVectorsRequest() {}
 
         if (in.readBoolean()) {
             doc = in.readBytesReference();
-            mediaType = in.readMediaType();
+            if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+                mediaType = in.readMediaType();
+            } else {
+                mediaType = in.readEnum(XContentType.class);
+            }
         }
         routing = in.readOptionalString();
         preference = in.readOptionalString();
@@ -533,7 +538,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeBoolean(doc != null);
         if (doc != null) {
             out.writeBytesReference(doc);
-            mediaType.writeTo(out);
+            if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+                mediaType.writeTo(out);
+            } else {
+                out.writeEnum((XContentType) mediaType);
+            }
         }
         out.writeOptionalString(routing);
         out.writeOptionalString(preference);
diff --git a/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java b/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java
index fea3be954b006..0208f027b76f5 100644
--- a/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java
+++ b/server/src/main/java/org/opensearch/extensions/rest/ExtensionRestRequest.java
@@ -9,10 +9,12 @@
 package org.opensearch.extensions.rest;
 
 import org.opensearch.OpenSearchParseException;
+import org.opensearch.Version;
 import org.opensearch.common.bytes.BytesReference;
 import org.opensearch.common.io.stream.StreamInput;
 import org.opensearch.common.io.stream.StreamOutput;
 import org.opensearch.common.xcontent.LoggingDeprecationHandler;
+import org.opensearch.common.xcontent.XContentType;
 import org.opensearch.core.xcontent.MediaType;
 import org.opensearch.core.xcontent.NamedXContentRegistry;
 import org.opensearch.core.xcontent.XContentParser;
@@ -102,7 +104,11 @@ public ExtensionRestRequest(StreamInput in) throws IOException {
         params = in.readMap(StreamInput::readString, StreamInput::readString);
         headers = in.readMap(StreamInput::readString, StreamInput::readStringList);
         if (in.readBoolean()) {
-            mediaType = in.readMediaType();
+            if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+                mediaType = in.readMediaType();
+            } else {
+                mediaType = in.readEnum(XContentType.class);
+            }
         }
         content = in.readBytesReference();
         principalIdentifierToken = in.readString();
@@ -119,7 +125,11 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeMap(headers, StreamOutput::writeString, StreamOutput::writeStringCollection);
         out.writeBoolean(mediaType != null);
         if (mediaType != null) {
-            mediaType.writeTo(out);
+            if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+                mediaType.writeTo(out);
+            } else {
+                out.writeEnum((XContentType) mediaType);
+            }
         }
         out.writeBytesReference(content);
         out.writeString(principalIdentifierToken);
diff --git a/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java b/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java
index b30a6a43027ef..2cdc8d559ba0f 100644
--- a/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java
+++ b/server/src/main/java/org/opensearch/index/query/MoreLikeThisQueryBuilder.java
@@ -235,7 +235,11 @@ public Item(@Nullable String index, XContentBuilder doc) {
             }
             if (in.readBoolean()) {
                 doc = (BytesReference) in.readGenericValue();
-                mediaType = in.readMediaType();
+                if (in.getVersion().onOrAfter(Version.V_3_0_0)) {
+                    mediaType = in.readMediaType();
+                } else {
+                    mediaType = in.readEnum(XContentType.class);
+                }
             } else {
                 id = in.readString();
             }
@@ -256,7 +260,11 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeBoolean(doc != null);
             if (doc != null) {
                 out.writeGenericValue(doc);
-                mediaType.writeTo(out);
+                if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+                    mediaType.writeTo(out);
+                } else {
+                    out.writeEnum((XContentType) mediaType);
+                }
             } else {
                 out.writeString(id);
             }
diff --git a/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java b/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java
index 4c94881db0b5e..48383b3fa16af 100644
--- a/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java
+++ b/server/src/main/java/org/opensearch/ingest/PipelineConfiguration.java
@@ -32,6 +32,7 @@
 
 package org.opensearch.ingest;
 
+import org.opensearch.Version;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
 import org.opensearch.core.ParseField;
@@ -137,7 +138,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     }
 
     public static PipelineConfiguration readFrom(StreamInput in) throws IOException {
-        return new PipelineConfiguration(in.readString(), in.readBytesReference(), in.readMediaType());
+        return new PipelineConfiguration(
+            in.readString(),
+            in.readBytesReference(),
+            in.getVersion().onOrAfter(Version.V_3_0_0) ? in.readMediaType() : in.readEnum(XContentType.class)
+        );
     }
 
     public static Diff<PipelineConfiguration> readDiffFrom(StreamInput in) throws IOException {
@@ -153,7 +158,11 @@ public String toString() {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeString(id);
         out.writeBytesReference(config);
-        mediaType.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override
diff --git a/server/src/main/java/org/opensearch/search/pipeline/PipelineConfiguration.java b/server/src/main/java/org/opensearch/search/pipeline/PipelineConfiguration.java
index 448eb581ba5e7..4308d988a77c5 100644
--- a/server/src/main/java/org/opensearch/search/pipeline/PipelineConfiguration.java
+++ b/server/src/main/java/org/opensearch/search/pipeline/PipelineConfiguration.java
@@ -8,6 +8,7 @@
 
 package org.opensearch.search.pipeline;
 
+import org.opensearch.Version;
 import org.opensearch.cluster.AbstractDiffable;
 import org.opensearch.cluster.Diff;
 import org.opensearch.common.Strings;
@@ -116,7 +117,11 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
     }
 
     public static PipelineConfiguration readFrom(StreamInput in) throws IOException {
-        return new PipelineConfiguration(in.readString(), in.readBytesReference(), in.readMediaType());
+        return new PipelineConfiguration(
+            in.readString(),
+            in.readBytesReference(),
+            in.getVersion().onOrAfter(Version.V_3_0_0) ? in.readMediaType() : in.readEnum(XContentType.class)
+        );
     }
 
     public static Diff<PipelineConfiguration> readDiffFrom(StreamInput in) throws IOException {
@@ -132,7 +137,11 @@ public String toString() {
     public void writeTo(StreamOutput out) throws IOException {
         out.writeString(id);
         out.writeBytesReference(config);
-        mediaType.writeTo(out);
+        if (out.getVersion().onOrAfter(Version.V_3_0_0)) {
+            mediaType.writeTo(out);
+        } else {
+            out.writeEnum((XContentType) mediaType);
+        }
     }
 
     @Override