diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3354d4e1..dee64d89 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Added option to pass custom headers to 'AWSV4SignerAsyncAuth' ([863](https://github.com/opensearch-project/opensearch-py/pull/863))
 - Added sync and async sample that uses `search_after` parameter ([859](https://github.com/opensearch-project/opensearch-py/pull/859))
 ### Updated APIs
+- Updated opensearch-py APIs to reflect [opensearch-api-specification@0ee21a8](https://github.com/opensearch-project/opensearch-api-specification/commit/0ee21a86580b04eb31e27c28d2bdcec6c59be2a0)
 ### Changed
 - Small refactor of AWS Signer classes for both sync and async clients ([866](https://github.com/opensearch-project/opensearch-py/pull/866))
 ### Deprecated
diff --git a/opensearchpy/_async/client/indices.py b/opensearchpy/_async/client/indices.py
index 99603830..74bfa6c2 100644
--- a/opensearchpy/_async/client/indices.py
+++ b/opensearchpy/_async/client/indices.py
@@ -1797,6 +1797,7 @@ async def recovery(
     )
     async def upgrade(
         self,
+        body: Any = None,
         index: Any = None,
         params: Any = None,
         headers: Any = None,
@@ -1832,7 +1833,11 @@ async def upgrade(
             operation has completed before returning. Default is false.
         """
         return await self.transport.perform_request(
-            "POST", _make_path(index, "_upgrade"), params=params, headers=headers
+            "POST",
+            _make_path(index, "_upgrade"),
+            params=params,
+            headers=headers,
+            body=body,
         )
 
     @query_params(
diff --git a/opensearchpy/client/indices.py b/opensearchpy/client/indices.py
index c4b2405c..07210bb8 100644
--- a/opensearchpy/client/indices.py
+++ b/opensearchpy/client/indices.py
@@ -1797,6 +1797,7 @@ def recovery(
     )
     def upgrade(
         self,
+        body: Any = None,
         index: Any = None,
         params: Any = None,
         headers: Any = None,
@@ -1832,7 +1833,11 @@ def upgrade(
             operation has completed before returning. Default is false.
         """
         return self.transport.perform_request(
-            "POST", _make_path(index, "_upgrade"), params=params, headers=headers
+            "POST",
+            _make_path(index, "_upgrade"),
+            params=params,
+            headers=headers,
+            body=body,
         )
 
     @query_params(