diff --git a/CHANGELOG.md b/CHANGELOG.md
index a061660dd..174c1342c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -19,6 +19,9 @@
   - [v1.3.0](services/opensearch/CHANGELOG.md#v130)
     - **Breaking Change/Fix:** `create_backup` operation now returns `CreateBackupResponseItem` instead of `List[CreateBackupResponseItem]`
       The return type now correctly models the actual JSON response, this operation was broken beforehand.
+- `postgresflex`:
+  - [v1.6.0](services/postgresflex/CHANGELOG.md#v160)
+    - **Breaking Change:** `class` attribute in `CloneInstanceOverrides` and `StorageCreate` model is now required (previously optional)
 - `rabbitmq`:
   - [v1.3.0](services/rabbitmq/CHANGELOG.md#v130)
     - **Breaking Change/Fix:** `create_backup` operation now returns `CreateBackupResponseItem` instead of `List[CreateBackupResponseItem]`
diff --git a/services/postgresflex/CHANGELOG.md b/services/postgresflex/CHANGELOG.md
index e2c6a588e..624a5c0eb 100644
--- a/services/postgresflex/CHANGELOG.md
+++ b/services/postgresflex/CHANGELOG.md
@@ -1,3 +1,6 @@
+## v1.6.0
+- **Breaking Change:** `class` attribute in `CloneInstanceOverrides` and `StorageCreate` model is now required (previously optional)
+
 ## v1.5.0
 - **Breaking Change:** The v3 API replaces the v2 API.
 
diff --git a/services/postgresflex/oas_commit b/services/postgresflex/oas_commit
index fd8ff3e68..e05d493f3 100644
--- a/services/postgresflex/oas_commit
+++ b/services/postgresflex/oas_commit
@@ -1 +1 @@
-c09e232a83532c75ca1041153e3ebc7ce2d50eb6
+da4701b7dbe20e984aef89711bb9ba716e19fcba
diff --git a/services/postgresflex/pyproject.toml b/services/postgresflex/pyproject.toml
index ef0292a58..e413f20b5 100644
--- a/services/postgresflex/pyproject.toml
+++ b/services/postgresflex/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "stackit-postgresflex"
-version = "v1.5.0"
+version = "v1.6.0"
 description = "STACKIT PostgreSQL Flex API"
 authors = [{ name = "STACKIT Developer Tools", email = "developer-tools@stackit.cloud" }]
 requires-python = ">=3.10,<4.0"
diff --git a/services/postgresflex/src/stackit/postgresflex/models/clone_instance_overrides.py b/services/postgresflex/src/stackit/postgresflex/models/clone_instance_overrides.py
index c3606edeb..af85a8e82 100644
--- a/services/postgresflex/src/stackit/postgresflex/models/clone_instance_overrides.py
+++ b/services/postgresflex/src/stackit/postgresflex/models/clone_instance_overrides.py
@@ -28,9 +28,7 @@ class CloneInstanceOverrides(BaseModel):
     CloneInstanceOverrides
     """  # noqa: E501
 
-    var_class: Optional[StrictStr] = Field(
-        default=None, description="The storage class for the storage.", alias="class"
-    )
+    var_class: StrictStr = Field(description="The storage class for the storage.", alias="class")
     name: Optional[Annotated[str, Field(min_length=3, strict=True, max_length=63)]] = Field(
         default=None,
         description="The name of the cloned instance. If not provided, the default naming behavior of appending '-clone' to the source instance name is used.",
diff --git a/services/postgresflex/src/stackit/postgresflex/models/storage_create.py b/services/postgresflex/src/stackit/postgresflex/models/storage_create.py
index 08a969564..944b8861e 100644
--- a/services/postgresflex/src/stackit/postgresflex/models/storage_create.py
+++ b/services/postgresflex/src/stackit/postgresflex/models/storage_create.py
@@ -28,9 +28,7 @@ class StorageCreate(BaseModel):
     The object containing information about the storage size and class.
     """  # noqa: E501
 
-    var_class: Optional[StrictStr] = Field(
-        default=None, description="The storage class for the storage.", alias="class"
-    )
+    var_class: StrictStr = Field(description="The storage class for the storage.", alias="class")
     size: StrictInt = Field(description="The storage size in Gigabytes.")
     __properties: ClassVar[List[str]] = ["class", "size"]
 
diff --git a/services/postgresflex/uv.lock b/services/postgresflex/uv.lock
index ccbb2672f..211f5109e 100644
--- a/services/postgresflex/uv.lock
+++ b/services/postgresflex/uv.lock
@@ -1057,7 +1057,7 @@ dev = [
 
 [[package]]
 name = "stackit-postgresflex"
-version = "1.5.0"
+version = "1.6.0"
 source = { editable = "." }
 dependencies = [
     { name = "pydantic" },