From 540ab67767ef9566f35b0086b7e7f7b13e5bb23b Mon Sep 17 00:00:00 2001
From: Tommy Crews <twcrews96@gmail.com>
Date: Wed, 25 Feb 2026 14:05:51 -0600
Subject: [PATCH 1/2] Add missing `JsonPropertyName` attributes.

---
 Crews.Web.JsonApiClient/JsonApiRelationship.cs | 2 ++
 Crews.Web.JsonApiClient/JsonApiResource.cs     | 1 +
 2 files changed, 3 insertions(+)

diff --git a/Crews.Web.JsonApiClient/JsonApiRelationship.cs b/Crews.Web.JsonApiClient/JsonApiRelationship.cs
index e6463c6..a20379c 100644
--- a/Crews.Web.JsonApiClient/JsonApiRelationship.cs
+++ b/Crews.Web.JsonApiClient/JsonApiRelationship.cs
@@ -44,6 +44,7 @@ public record JsonApiRelationship<T> : JsonApiRelationship where T : JsonApiReso
     /// <summary>
     /// Gets or sets the data payload associated with the response or request.
     /// </summary>
+    [JsonPropertyName("data")]
     public new T? Data { get; init; }
 }
 
@@ -59,5 +60,6 @@ public record JsonApiCollectionRelationship<T> : JsonApiRelationship where T : I
     /// <summary>
     /// Gets or sets the data payload associated with the response or request.
     /// </summary>
+    [JsonPropertyName("data")]
     public new T? Data { get; init; }
 }
\ No newline at end of file
diff --git a/Crews.Web.JsonApiClient/JsonApiResource.cs b/Crews.Web.JsonApiClient/JsonApiResource.cs
index ae0e7b0..f0ba547 100644
--- a/Crews.Web.JsonApiClient/JsonApiResource.cs
+++ b/Crews.Web.JsonApiClient/JsonApiResource.cs
@@ -43,6 +43,7 @@ public record JsonApiResource<T> : JsonApiResource
     /// <summary>
     /// Gets or sets the collection of custom attributes associated with this object.
     /// </summary>
+    [JsonPropertyName("attributes")]
     public new T? Attributes { get; init; }
 }
 

From 6a54101af282120282227dce680253c1803b3f03 Mon Sep 17 00:00:00 2001
From: Tommy Crews <twcrews96@gmail.com>
Date: Wed, 25 Feb 2026 14:13:06 -0600
Subject: [PATCH 2/2] Bump version and update changelog.

---
 CHANGELOG.md                                   | 18 ++++++++++++++++++
 .../Crews.Web.JsonApiClient.csproj             |  2 +-
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 136e87b..337b45f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,23 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [5.2.1] - 2026-02-25
+
+### Fixed
+
+Add missing `[JsonPropertyName]` attributes to properties in the following derived classes:
+
+- `JsonApiResource<T>.Attributes`
+- `JsonApiRelationship<T>.Data`
+- `JsonApiCollectionRelationship<T>.Data`
+
+### Remarks
+
+This change addresses an oversight in previous versions of the library in which some derived generic class properties were missing the `JsonPropertyName` attribute. This introduced errors in the deserialization and serialization processes:
+
+- Deserialized documents would set the property values for the base class, losing the advantage of the generic type property.
+- Serialized documents would produce a second property without the overriding `JsonPropertyName`, falling back to the active `JsonSerializerOptions` instance (if any).
+
 ## [5.2.0] - 2026-02-25
 
 ### Changed
@@ -118,6 +135,7 @@ Additionally, this version aims to be more idiomatic by renaming class propertie
 
 Initial release.
 
+[5.2.1]: https://github.com/twcrews/jsonapi-client/compare/5.2.0...5.2.1
 [5.2.0]: https://github.com/twcrews/jsonapi-client/compare/5.1.0...5.2.0
 [5.1.0]: https://github.com/twcrews/jsonapi-client/compare/5.0.0...5.1.0
 [5.0.0]: https://github.com/twcrews/jsonapi-client/compare/4.0.0...5.0.0
diff --git a/Crews.Web.JsonApiClient/Crews.Web.JsonApiClient.csproj b/Crews.Web.JsonApiClient/Crews.Web.JsonApiClient.csproj
index 151f1fd..c10e9ec 100644
--- a/Crews.Web.JsonApiClient/Crews.Web.JsonApiClient.csproj
+++ b/Crews.Web.JsonApiClient/Crews.Web.JsonApiClient.csproj
@@ -9,7 +9,7 @@
 
   <PropertyGroup>
     <PackageId>Crews.Web.JsonApiClient</PackageId>
-    <PackageVersion>5.2.0</PackageVersion>
+    <PackageVersion>5.2.1</PackageVersion>
     <Authors>Tommy Crews</Authors>
     <Description>
       A library containing serialization models and methods for the JSON:API specification.