diff --git a/langfuse/api/reference.md b/langfuse/api/reference.md
index 759ddbdec..19870d547 100644
--- a/langfuse/api/reference.md
+++ b/langfuse/api/reference.md
@@ -5222,7 +5222,6 @@ client = FernLangfuse(
 client.projects.update(
     project_id="projectId",
     name="name",
-    retention=1,
 )
 
 ```
@@ -5255,7 +5254,7 @@ client.projects.update(
 <dl>
 <dd>
 
-**retention:** `int` — Number of days to retain data. Must be 0 or at least 3 days. Requires data-retention entitlement for non-zero values. Optional.
+**metadata:** `typing.Optional[typing.Dict[str, typing.Any]]` — Optional metadata for the project
     
 </dd>
 </dl>
@@ -5263,7 +5262,12 @@ client.projects.update(
 <dl>
 <dd>
 
-**metadata:** `typing.Optional[typing.Dict[str, typing.Any]]` — Optional metadata for the project
+**retention:** `typing.Optional[int]` 
+
+Number of days to retain data.
+Must be 0 or at least 3 days.
+Requires data-retention entitlement for non-zero values.
+Optional. Will retain existing retention setting if omitted.
     
 </dd>
 </dl>
diff --git a/langfuse/api/resources/projects/client.py b/langfuse/api/resources/projects/client.py
index 5af232dfb..3db173d75 100644
--- a/langfuse/api/resources/projects/client.py
+++ b/langfuse/api/resources/projects/client.py
@@ -169,8 +169,8 @@ def update(
         project_id: str,
         *,
         name: str,
-        retention: int,
         metadata: typing.Optional[typing.Dict[str, typing.Any]] = OMIT,
+        retention: typing.Optional[int] = OMIT,
         request_options: typing.Optional[RequestOptions] = None,
     ) -> Project:
         """
@@ -182,12 +182,15 @@ def update(
 
         name : str
 
-        retention : int
-            Number of days to retain data. Must be 0 or at least 3 days. Requires data-retention entitlement for non-zero values. Optional.
-
         metadata : typing.Optional[typing.Dict[str, typing.Any]]
             Optional metadata for the project
 
+        retention : typing.Optional[int]
+            Number of days to retain data.
+            Must be 0 or at least 3 days.
+            Requires data-retention entitlement for non-zero values.
+            Optional. Will retain existing retention setting if omitted.
+
         request_options : typing.Optional[RequestOptions]
             Request-specific configuration.
 
@@ -210,7 +213,6 @@ def update(
         client.projects.update(
             project_id="projectId",
             name="name",
-            retention=1,
         )
         """
         _response = self._client_wrapper.httpx_client.request(
@@ -698,8 +700,8 @@ async def update(
         project_id: str,
         *,
         name: str,
-        retention: int,
         metadata: typing.Optional[typing.Dict[str, typing.Any]] = OMIT,
+        retention: typing.Optional[int] = OMIT,
         request_options: typing.Optional[RequestOptions] = None,
     ) -> Project:
         """
@@ -711,12 +713,15 @@ async def update(
 
         name : str
 
-        retention : int
-            Number of days to retain data. Must be 0 or at least 3 days. Requires data-retention entitlement for non-zero values. Optional.
-
         metadata : typing.Optional[typing.Dict[str, typing.Any]]
             Optional metadata for the project
 
+        retention : typing.Optional[int]
+            Number of days to retain data.
+            Must be 0 or at least 3 days.
+            Requires data-retention entitlement for non-zero values.
+            Optional. Will retain existing retention setting if omitted.
+
         request_options : typing.Optional[RequestOptions]
             Request-specific configuration.
 
@@ -744,7 +749,6 @@ async def main() -> None:
             await client.projects.update(
                 project_id="projectId",
                 name="name",
-                retention=1,
             )