diff --git a/services/postgresflex/src/stackit/postgresflex/__init__.py b/services/postgresflex/src/stackit/postgresflex/__init__.py
index dc98383f2..8abff3da0 100644
--- a/services/postgresflex/src/stackit/postgresflex/__init__.py
+++ b/services/postgresflex/src/stackit/postgresflex/__init__.py
@@ -78,6 +78,7 @@
     "ResetUserResponse",
     "Storage",
     "StorageRange",
+    "StorageUpdate",
     "UpdateBackupSchedulePayload",
     "UpdateInstancePayload",
     "UpdateUserPayload",
@@ -231,6 +232,7 @@
 )
 from stackit.postgresflex.models.storage import Storage as Storage
 from stackit.postgresflex.models.storage_range import StorageRange as StorageRange
+from stackit.postgresflex.models.storage_update import StorageUpdate as StorageUpdate
 from stackit.postgresflex.models.update_backup_schedule_payload import (
     UpdateBackupSchedulePayload as UpdateBackupSchedulePayload,
 )
diff --git a/services/postgresflex/src/stackit/postgresflex/models/__init__.py b/services/postgresflex/src/stackit/postgresflex/models/__init__.py
index f7a8fbaf5..b7612075b 100644
--- a/services/postgresflex/src/stackit/postgresflex/models/__init__.py
+++ b/services/postgresflex/src/stackit/postgresflex/models/__init__.py
@@ -92,6 +92,7 @@
 from stackit.postgresflex.models.reset_user_response import ResetUserResponse
 from stackit.postgresflex.models.storage import Storage
 from stackit.postgresflex.models.storage_range import StorageRange
+from stackit.postgresflex.models.storage_update import StorageUpdate
 from stackit.postgresflex.models.update_backup_schedule_payload import (
     UpdateBackupSchedulePayload,
 )
diff --git a/services/postgresflex/src/stackit/postgresflex/models/instance_data_point.py b/services/postgresflex/src/stackit/postgresflex/models/instance_data_point.py
index 1ad978051..8ebb41645 100644
--- a/services/postgresflex/src/stackit/postgresflex/models/instance_data_point.py
+++ b/services/postgresflex/src/stackit/postgresflex/models/instance_data_point.py
@@ -18,7 +18,13 @@
 import pprint
 from typing import Any, ClassVar, Dict, List, Optional, Set, Union
 
-from pydantic import BaseModel, ConfigDict, StrictFloat, StrictInt, StrictStr
+from pydantic import (
+    BaseModel,
+    ConfigDict,
+    StrictFloat,
+    StrictInt,
+    StrictStr,
+)
 from typing_extensions import Self
 
 
diff --git a/services/postgresflex/src/stackit/postgresflex/models/partial_update_instance_payload.py b/services/postgresflex/src/stackit/postgresflex/models/partial_update_instance_payload.py
index e8a6ef7ae..b90ddd023 100644
--- a/services/postgresflex/src/stackit/postgresflex/models/partial_update_instance_payload.py
+++ b/services/postgresflex/src/stackit/postgresflex/models/partial_update_instance_payload.py
@@ -22,7 +22,7 @@
 from typing_extensions import Self
 
 from stackit.postgresflex.models.acl import ACL
-from stackit.postgresflex.models.storage import Storage
+from stackit.postgresflex.models.storage_update import StorageUpdate
 
 
 class PartialUpdateInstancePayload(BaseModel):
@@ -37,7 +37,7 @@ class PartialUpdateInstancePayload(BaseModel):
     name: Optional[StrictStr] = None
     options: Optional[Dict[str, StrictStr]] = None
     replicas: Optional[StrictInt] = None
-    storage: Optional[Storage] = None
+    storage: Optional[StorageUpdate] = None
     version: Optional[StrictStr] = None
     __properties: ClassVar[List[str]] = [
         "acl",
@@ -114,7 +114,7 @@ def from_dict(cls, obj: Optional[Dict[str, Any]]) -> Optional[Self]:
                 "name": obj.get("name"),
                 "options": obj.get("options"),
                 "replicas": obj.get("replicas"),
-                "storage": Storage.from_dict(obj["storage"]) if obj.get("storage") is not None else None,
+                "storage": StorageUpdate.from_dict(obj["storage"]) if obj.get("storage") is not None else None,
                 "version": obj.get("version"),
             }
         )
diff --git a/services/postgresflex/src/stackit/postgresflex/models/postgres_database_parameter.py b/services/postgresflex/src/stackit/postgresflex/models/postgres_database_parameter.py
index b5bd1a1c7..a4a14f17b 100644
--- a/services/postgresflex/src/stackit/postgresflex/models/postgres_database_parameter.py
+++ b/services/postgresflex/src/stackit/postgresflex/models/postgres_database_parameter.py
@@ -18,7 +18,13 @@
 import pprint
 from typing import Any, ClassVar, Dict, List, Optional, Set
 
-from pydantic import BaseModel, ConfigDict, Field, StrictBool, StrictStr
+from pydantic import (
+    BaseModel,
+    ConfigDict,
+    Field,
+    StrictBool,
+    StrictStr,
+)
 from typing_extensions import Self
 
 
diff --git a/services/postgresflex/src/stackit/postgresflex/models/storage_update.py b/services/postgresflex/src/stackit/postgresflex/models/storage_update.py
new file mode 100644
index 000000000..d7dc0de24
--- /dev/null
+++ b/services/postgresflex/src/stackit/postgresflex/models/storage_update.py
@@ -0,0 +1,87 @@
+# coding: utf-8
+
+"""
+    STACKIT PostgreSQL Flex API
+
+    This is the documentation for the STACKIT postgres service
+
+    The version of the OpenAPI document: 2.0.0
+    Contact: support@stackit.cloud
+    Generated by OpenAPI Generator (https://openapi-generator.tech)
+
+    Do not edit the class manually.
+"""  # noqa: E501
+
+from __future__ import annotations
+
+import json
+import pprint
+from typing import Any, ClassVar, Dict, List, Optional, Set
+
+from pydantic import BaseModel, ConfigDict, Field, StrictInt, StrictStr
+from typing_extensions import Self
+
+
+class StorageUpdate(BaseModel):
+    """
+    StorageUpdate
+    """  # noqa: E501
+
+    var_class: Optional[StrictStr] = Field(
+        default=None,
+        description=" ⚠️ **DEPRECATED AND NON-FUNCTIONAL:** Updating the performance class field is not possible. ",
+        alias="class",
+    )
+    size: Optional[StrictInt] = None
+    __properties: ClassVar[List[str]] = ["class", "size"]
+
+    model_config = ConfigDict(
+        populate_by_name=True,
+        validate_assignment=True,
+        protected_namespaces=(),
+    )
+
+    def to_str(self) -> str:
+        """Returns the string representation of the model using alias"""
+        return pprint.pformat(self.model_dump(by_alias=True))
+
+    def to_json(self) -> str:
+        """Returns the JSON representation of the model using alias"""
+        # TODO: pydantic v2: use .model_dump_json(by_alias=True, exclude_unset=True) instead
+        return json.dumps(self.to_dict())
+
+    @classmethod
+    def from_json(cls, json_str: str) -> Optional[Self]:
+        """Create an instance of StorageUpdate from a JSON string"""
+        return cls.from_dict(json.loads(json_str))
+
+    def to_dict(self) -> Dict[str, Any]:
+        """Return the dictionary representation of the model using alias.
+
+        This has the following differences from calling pydantic's
+        `self.model_dump(by_alias=True)`:
+
+        * `None` is only added to the output dict for nullable fields that
+          were set at model initialization. Other fields with value `None`
+          are ignored.
+        """
+        excluded_fields: Set[str] = set([])
+
+        _dict = self.model_dump(
+            by_alias=True,
+            exclude=excluded_fields,
+            exclude_none=True,
+        )
+        return _dict
+
+    @classmethod
+    def from_dict(cls, obj: Optional[Dict[str, Any]]) -> Optional[Self]:
+        """Create an instance of StorageUpdate from a dict"""
+        if obj is None:
+            return None
+
+        if not isinstance(obj, dict):
+            return cls.model_validate(obj)
+
+        _obj = cls.model_validate({"class": obj.get("class"), "size": obj.get("size")})
+        return _obj
diff --git a/services/postgresflex/src/stackit/postgresflex/models/update_instance_payload.py b/services/postgresflex/src/stackit/postgresflex/models/update_instance_payload.py
index 52c40f616..bd7e8a93a 100644
--- a/services/postgresflex/src/stackit/postgresflex/models/update_instance_payload.py
+++ b/services/postgresflex/src/stackit/postgresflex/models/update_instance_payload.py
@@ -22,7 +22,7 @@
 from typing_extensions import Self
 
 from stackit.postgresflex.models.acl import ACL
-from stackit.postgresflex.models.storage import Storage
+from stackit.postgresflex.models.storage_update import StorageUpdate
 
 
 class UpdateInstancePayload(BaseModel):
@@ -37,7 +37,7 @@ class UpdateInstancePayload(BaseModel):
     name: Optional[StrictStr] = None
     options: Optional[Dict[str, StrictStr]] = None
     replicas: Optional[StrictInt] = None
-    storage: Optional[Storage] = None
+    storage: Optional[StorageUpdate] = None
     version: Optional[StrictStr] = None
     __properties: ClassVar[List[str]] = [
         "acl",
@@ -114,7 +114,7 @@ def from_dict(cls, obj: Optional[Dict[str, Any]]) -> Optional[Self]:
                 "name": obj.get("name"),
                 "options": obj.get("options"),
                 "replicas": obj.get("replicas"),
-                "storage": Storage.from_dict(obj["storage"]) if obj.get("storage") is not None else None,
+                "storage": StorageUpdate.from_dict(obj["storage"]) if obj.get("storage") is not None else None,
                 "version": obj.get("version"),
             }
         )