diff --git a/.gitignore b/.gitignore
index d8abd2df1..1f15093f3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -56,6 +56,9 @@ opensearch*
 # documentation
 docs/
 
+# temporary
+tmp/
+
 test/benchmarks/macro/fixtures/*
 
 *-junit.xml
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7fd805ebe..5b64495ab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Documented Transport#request ([#335](https://github.com/opensearch-project/opensearch-js/issues/335))
 - Documented all API methods ([#335](https://github.com/opensearch-project/opensearch-js/issues/335))
 - Added point in time APIs ([#348](https://github.com/opensearch-project/opensearch-js/pull/348))
+- Added support for Amazon OpenSearch Serverless ([#356](https://github.com/opensearch-project/opensearch-js/issues/356))
+
 ### Dependencies
 - Bumps `xmlbuilder2` from 2.4.1 to 3.0.2
 - Bumps `minimatch` from 3.0.4 to 3.1.2
@@ -49,4 +51,4 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Fix mutability of connection headers ([#291](https://github.com/opensearch-project/opensearch-js/issues/291))
 
 [2.1]: https://github.com/opensearch-project/opensearch-js/releases/tag/2.1.0
-[Unreleased]: https://github.com/opensearch-project/opensearch-js/compare/2.1...HEAD
\ No newline at end of file
+[Unreleased]: https://github.com/opensearch-project/opensearch-js/compare/2.1...HEAD
diff --git a/lib/aws/AwsSigv4Signer.js b/lib/aws/AwsSigv4Signer.js
index 4e1e74d43..d46ba351d 100644
--- a/lib/aws/AwsSigv4Signer.js
+++ b/lib/aws/AwsSigv4Signer.js
@@ -13,6 +13,7 @@ const Connection = require('../Connection');
 const Transport = require('../Transport');
 const aws4 = require('aws4');
 const AwsSigv4SignerError = require('./errors');
+const crypto = require('crypto');
 
 const getAwsSDKCredentialsProvider = async () => {
   // First try V3
@@ -77,7 +78,12 @@ function AwsSigv4Signer(opts = {}) {
     request.region = opts.region;
     request.headers = request.headers || {};
     request.headers['host'] = request.hostname;
-    return aws4.sign(request, credentialsState.credentials);
+    const signed = aws4.sign(request, credentialsState.credentials);
+    signed.headers['x-amz-content-sha256'] = crypto
+      .createHash('sha256')
+      .update(request.body || '', 'utf8')
+      .digest('hex');
+    return signed;
   }
 
   class AwsSigv4SignerConnection extends Connection {
diff --git a/package.json b/package.json
index 912a18efd..62cbedb14 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,7 @@
     }
   },
   "homepage": "https://www.opensearch.org/",
-  "version": "2.1.1",
+  "version": "2.2.0",
   "versionCanary": "7.10.0-canary.6",
   "keywords": [
     "opensearch",
diff --git a/test/unit/lib/aws/awssigv4signer.test.js b/test/unit/lib/aws/awssigv4signer.test.js
index b15fb51b7..7c8636fe3 100644
--- a/test/unit/lib/aws/awssigv4signer.test.js
+++ b/test/unit/lib/aws/awssigv4signer.test.js
@@ -16,7 +16,7 @@ const { Connection } = require('../../../../index');
 const { Client, buildServer } = require('../../../utils');
 
 test('Sign with SigV4', (t) => {
-  t.plan(3);
+  t.plan(4);
 
   const mockCreds = {
     accessKeyId: uuidv4(),
@@ -50,6 +50,10 @@ test('Sign with SigV4', (t) => {
   const signedRequest = auth.buildSignedRequestObject(request);
   t.hasProp(signedRequest.headers, 'X-Amz-Date');
   t.hasProp(signedRequest.headers, 'Authorization');
+  t.same(
+    signedRequest.headers['x-amz-content-sha256'],
+    'e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855'
+  );
   t.same(signedRequest.service, 'es');
 });