diff --git a/openapi-raw.yaml b/openapi-raw.yaml
index a99c6c809..4920f55a7 100644
--- a/openapi-raw.yaml
+++ b/openapi-raw.yaml
@@ -10417,7 +10417,7 @@ components:
         fax_pages_sent:
           description: '_t__AccountUsage::FAX_PAGES_SENT'
           type: integer
-          default: 0
+          nullable: true
       type: object
       x-internal-class: true
     AccountVerifyResponseAccount:
diff --git a/openapi-sdk.yaml b/openapi-sdk.yaml
index 2dd05ea98..fe81aca41 100644
--- a/openapi-sdk.yaml
+++ b/openapi-sdk.yaml
@@ -11025,7 +11025,7 @@ components:
         fax_pages_sent:
           description: 'Number of fax pages sent'
           type: integer
-          default: 0
+          nullable: true
       type: object
       x-internal-class: true
     AccountVerifyResponseAccount:
diff --git a/openapi.yaml b/openapi.yaml
index 4bc57f3d1..e49cd747a 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -11003,7 +11003,7 @@ components:
         fax_pages_sent:
           description: 'Number of fax pages sent'
           type: integer
-          default: 0
+          nullable: true
       type: object
       x-internal-class: true
     AccountVerifyResponseAccount:
diff --git a/sdks/dotnet/docs/AccountResponseUsage.md b/sdks/dotnet/docs/AccountResponseUsage.md
index 27e541f8f..fa5536881 100644
--- a/sdks/dotnet/docs/AccountResponseUsage.md
+++ b/sdks/dotnet/docs/AccountResponseUsage.md
@@ -5,7 +5,7 @@ Details concerning monthly usage
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-**FaxPagesSent** | **int** |  Number of fax pages sent  | [optional] [default to 0]
+**FaxPagesSent** | **int?** |  Number of fax pages sent  | [optional] 
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/sdks/dotnet/src/Dropbox.Sign/Model/AccountResponseUsage.cs b/sdks/dotnet/src/Dropbox.Sign/Model/AccountResponseUsage.cs
index dd51fdcb5..bd9e2e5ac 100644
--- a/sdks/dotnet/src/Dropbox.Sign/Model/AccountResponseUsage.cs
+++ b/sdks/dotnet/src/Dropbox.Sign/Model/AccountResponseUsage.cs
@@ -41,8 +41,8 @@ protected AccountResponseUsage() { }
         /// <summary>
         /// Initializes a new instance of the <see cref="AccountResponseUsage" /> class.
         /// </summary>
-        /// <param name="faxPagesSent">Number of fax pages sent (default to 0).</param>
-        public AccountResponseUsage(int faxPagesSent = 0)
+        /// <param name="faxPagesSent">Number of fax pages sent.</param>
+        public AccountResponseUsage(int? faxPagesSent = default(int?))
         {
 
             this.FaxPagesSent = faxPagesSent;
@@ -69,7 +69,7 @@ public static AccountResponseUsage Init(string jsonData)
         /// </summary>
         /// <value>Number of fax pages sent</value>
         [DataMember(Name = "fax_pages_sent", EmitDefaultValue = true)]
-        public int FaxPagesSent { get; set; }
+        public int? FaxPagesSent { get; set; }
 
         /// <summary>
         /// Returns the string presentation of the object
@@ -117,7 +117,8 @@ public bool Equals(AccountResponseUsage input)
             return
                 (
                     this.FaxPagesSent == input.FaxPagesSent ||
-                    this.FaxPagesSent.Equals(input.FaxPagesSent)
+                    (this.FaxPagesSent != null &&
+                    this.FaxPagesSent.Equals(input.FaxPagesSent))
                 );
         }
 
@@ -130,7 +131,10 @@ public override int GetHashCode()
             unchecked // Overflow is fine, just wrap
             {
                 int hashCode = 41;
-                hashCode = (hashCode * 59) + this.FaxPagesSent.GetHashCode();
+                if (this.FaxPagesSent != null)
+                {
+                    hashCode = (hashCode * 59) + this.FaxPagesSent.GetHashCode();
+                }
                 return hashCode;
             }
         }
@@ -151,7 +155,7 @@ public List<OpenApiType> GetOpenApiTypes()
             {
                 Name = "fax_pages_sent",
                 Property = "FaxPagesSent",
-                Type = "int",
+                Type = "int?",
                 Value = FaxPagesSent,
             });
 
diff --git a/sdks/java-v1/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java b/sdks/java-v1/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java
index c45fe4ce2..daac05931 100644
--- a/sdks/java-v1/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java
+++ b/sdks/java-v1/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java
@@ -31,7 +31,7 @@
 @JsonIgnoreProperties(ignoreUnknown = true)
 public class AccountResponseUsage {
     public static final String JSON_PROPERTY_FAX_PAGES_SENT = "fax_pages_sent";
-    private Integer faxPagesSent = 0;
+    private Integer faxPagesSent;
 
     public AccountResponseUsage() {}
 
diff --git a/sdks/java-v2/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java b/sdks/java-v2/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java
index 34dc9f8c0..741d5e58c 100644
--- a/sdks/java-v2/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java
+++ b/sdks/java-v2/src/main/java/com/dropbox/sign/model/AccountResponseUsage.java
@@ -39,7 +39,7 @@
 @JsonIgnoreProperties(ignoreUnknown=true)
 public class AccountResponseUsage {
   public static final String JSON_PROPERTY_FAX_PAGES_SENT = "fax_pages_sent";
-  private Integer faxPagesSent = 0;
+  private Integer faxPagesSent;
 
   public AccountResponseUsage() { 
   }
diff --git a/sdks/node/dist/api.js b/sdks/node/dist/api.js
index d06b3bae1..e92bff233 100644
--- a/sdks/node/dist/api.js
+++ b/sdks/node/dist/api.js
@@ -16568,9 +16568,6 @@ AccountResponseQuotas.attributeTypeMap = [
 
 // model/accountResponseUsage.ts
 var _AccountResponseUsage = class {
-  constructor() {
-    this["faxPagesSent"] = 0;
-  }
   static getAttributeTypeMap() {
     return _AccountResponseUsage.attributeTypeMap;
   }
diff --git a/sdks/node/docs/model/AccountResponseUsage.md b/sdks/node/docs/model/AccountResponseUsage.md
index 0591e3c98..2f095fba9 100644
--- a/sdks/node/docs/model/AccountResponseUsage.md
+++ b/sdks/node/docs/model/AccountResponseUsage.md
@@ -6,6 +6,6 @@ Details concerning monthly usage
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-| `faxPagesSent` | ```number``` |  Number of fax pages sent  |  [default to 0] |
+| `faxPagesSent` | ```number``` |  Number of fax pages sent  |  |
 
 [[Back to Model list]](../../README.md#models) [[Back to API list]](../../README.md#endpoints) [[Back to README]](../../README.md)
diff --git a/sdks/node/model/accountResponseUsage.ts b/sdks/node/model/accountResponseUsage.ts
index ce2d969c0..95f6f9f88 100644
--- a/sdks/node/model/accountResponseUsage.ts
+++ b/sdks/node/model/accountResponseUsage.ts
@@ -31,7 +31,7 @@ export class AccountResponseUsage {
   /**
    * Number of fax pages sent
    */
-  "faxPagesSent"?: number = 0;
+  "faxPagesSent"?: number | null;
 
   static discriminator: string | undefined = undefined;
 
diff --git a/sdks/node/types/model/accountResponseUsage.d.ts b/sdks/node/types/model/accountResponseUsage.d.ts
index 0b520ac76..7506ca0ee 100644
--- a/sdks/node/types/model/accountResponseUsage.d.ts
+++ b/sdks/node/types/model/accountResponseUsage.d.ts
@@ -1,6 +1,6 @@
 import { AttributeTypeMap } from "./";
 export declare class AccountResponseUsage {
-    "faxPagesSent"?: number;
+    "faxPagesSent"?: number | null;
     static discriminator: string | undefined;
     static attributeTypeMap: AttributeTypeMap;
     static getAttributeTypeMap(): AttributeTypeMap;
diff --git a/sdks/php/docs/Model/AccountResponseUsage.md b/sdks/php/docs/Model/AccountResponseUsage.md
index c87b1422d..3d8c992c2 100644
--- a/sdks/php/docs/Model/AccountResponseUsage.md
+++ b/sdks/php/docs/Model/AccountResponseUsage.md
@@ -6,6 +6,6 @@ Details concerning monthly usage
 
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-| `fax_pages_sent` | ```int``` |  Number of fax pages sent  |  [default to 0] |
+| `fax_pages_sent` | ```int``` |  Number of fax pages sent  |  |
 
 [[Back to Model list]](../../README.md#models) [[Back to API list]](../../README.md#endpoints) [[Back to README]](../../README.md)
diff --git a/sdks/php/src/Model/AccountResponseUsage.php b/sdks/php/src/Model/AccountResponseUsage.php
index 6728300ac..94eb509e7 100644
--- a/sdks/php/src/Model/AccountResponseUsage.php
+++ b/sdks/php/src/Model/AccountResponseUsage.php
@@ -29,7 +29,6 @@
 
 use ArrayAccess;
 use Dropbox\Sign\ObjectSerializer;
-use InvalidArgumentException;
 use JsonSerializable;
 use ReturnTypeWillChange;
 
@@ -78,7 +77,7 @@ class AccountResponseUsage implements ModelInterface, ArrayAccess, JsonSerializa
      * @var bool[]
      */
     protected static array $openAPINullables = [
-        'fax_pages_sent' => false,
+        'fax_pages_sent' => true,
     ];
 
     /**
@@ -236,7 +235,7 @@ public function getModelName()
      */
     public function __construct(array $data = null)
     {
-        $this->setIfExists('fax_pages_sent', $data ?? [], 0);
+        $this->setIfExists('fax_pages_sent', $data ?? [], null);
     }
 
     /**
@@ -316,7 +315,14 @@ public function getFaxPagesSent()
     public function setFaxPagesSent(?int $fax_pages_sent)
     {
         if (is_null($fax_pages_sent)) {
-            throw new InvalidArgumentException('non-nullable fax_pages_sent cannot be null');
+            array_push($this->openAPINullablesSetToNull, 'fax_pages_sent');
+        } else {
+            $nullablesSetToNull = $this->getOpenAPINullablesSetToNull();
+            $index = array_search('fax_pages_sent', $nullablesSetToNull);
+            if ($index !== false) {
+                unset($nullablesSetToNull[$index]);
+                $this->setOpenAPINullablesSetToNull($nullablesSetToNull);
+            }
         }
         $this->container['fax_pages_sent'] = $fax_pages_sent;
 
diff --git a/sdks/python/docs/AccountResponseUsage.md b/sdks/python/docs/AccountResponseUsage.md
index a8ca8e606..dd99429af 100644
--- a/sdks/python/docs/AccountResponseUsage.md
+++ b/sdks/python/docs/AccountResponseUsage.md
@@ -5,7 +5,7 @@ Details concerning monthly usage
 ## Properties
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
-| `fax_pages_sent` | ```int``` |  Number of fax pages sent  |  [default to 0] |
+| `fax_pages_sent` | ```int``` |  Number of fax pages sent  |  |
 
 [[Back to Model list]](../README.md#documentation-for-models) [[Back to API list]](../README.md#documentation-for-api-endpoints) [[Back to README]](../README.md)
 
diff --git a/sdks/python/dropbox_sign/models/account_response_usage.py b/sdks/python/dropbox_sign/models/account_response_usage.py
index 84e6f9841..8efc7a64b 100644
--- a/sdks/python/dropbox_sign/models/account_response_usage.py
+++ b/sdks/python/dropbox_sign/models/account_response_usage.py
@@ -33,7 +33,7 @@ class AccountResponseUsage(BaseModel):
     """  # noqa: E501
 
     fax_pages_sent: Optional[StrictInt] = Field(
-        default=0, description="Number of fax pages sent"
+        default=None, description="Number of fax pages sent"
     )
     __properties: ClassVar[List[str]] = ["fax_pages_sent"]
 
@@ -98,15 +98,7 @@ def from_dict(cls, obj: Optional[Dict[str, Any]]) -> Optional[Self]:
         if not isinstance(obj, dict):
             return cls.model_validate(obj)
 
-        _obj = cls.model_validate(
-            {
-                "fax_pages_sent": (
-                    obj.get("fax_pages_sent")
-                    if obj.get("fax_pages_sent") is not None
-                    else 0
-                )
-            }
-        )
+        _obj = cls.model_validate({"fax_pages_sent": obj.get("fax_pages_sent")})
         return _obj
 
     @classmethod
diff --git a/sdks/ruby/docs/AccountResponseUsage.md b/sdks/ruby/docs/AccountResponseUsage.md
index 85145219a..6dc2ddc21 100644
--- a/sdks/ruby/docs/AccountResponseUsage.md
+++ b/sdks/ruby/docs/AccountResponseUsage.md
@@ -6,5 +6,5 @@ Details concerning monthly usage
 
 | Name | Type | Description | Notes |
 | ---- | ---- | ----------- | ----- |
-| `fax_pages_sent` | ```Integer``` |  Number of fax pages sent  |  [default to 0] |
+| `fax_pages_sent` | ```Integer``` |  Number of fax pages sent  |  |
 
diff --git a/sdks/ruby/lib/dropbox-sign/models/account_response_usage.rb b/sdks/ruby/lib/dropbox-sign/models/account_response_usage.rb
index fe57fc441..3eb518794 100644
--- a/sdks/ruby/lib/dropbox-sign/models/account_response_usage.rb
+++ b/sdks/ruby/lib/dropbox-sign/models/account_response_usage.rb
@@ -20,7 +20,7 @@ module Dropbox::Sign
   # Details concerning monthly usage
   class AccountResponseUsage
     # Number of fax pages sent
-    # @return [Integer]
+    # @return [Integer, nil]
     attr_accessor :fax_pages_sent
 
     # Attribute mapping from ruby-style variable name to JSON key.
@@ -45,6 +45,7 @@ def self.openapi_types
     # List of attributes with nullable: true
     def self.openapi_nullable
       Set.new([
+        :'fax_pages_sent'
       ])
     end
 
@@ -90,8 +91,6 @@ def initialize(attributes = {})
 
       if attributes.key?(:'fax_pages_sent')
         self.fax_pages_sent = attributes[:'fax_pages_sent']
-      else
-        self.fax_pages_sent = 0
       end
     end