diff --git a/src/JsonApiDotNetCore/Middleware/HeaderConstants.cs b/src/JsonApiDotNetCore/Middleware/HeaderConstants.cs
index 190efb74f..05ddc69a6 100644
--- a/src/JsonApiDotNetCore/Middleware/HeaderConstants.cs
+++ b/src/JsonApiDotNetCore/Middleware/HeaderConstants.cs
@@ -14,5 +14,5 @@ public static class HeaderConstants
     public const string AtomicOperationsMediaType = $"{MediaType}; ext=\"https://jsonapi.org/ext/atomic\"";
 
     [Obsolete($"Use {nameof(JsonApiMediaType)}.{nameof(JsonApiMediaType.RelaxedAtomicOperations)}.ToString() instead.")]
-    public const string RelaxedAtomicOperationsMediaType = $"{MediaType}; ext=atomic-operations";
+    public const string RelaxedAtomicOperationsMediaType = $"{MediaType}; ext=atomic";
 }
diff --git a/src/JsonApiDotNetCore/Middleware/JsonApiMediaType.cs b/src/JsonApiDotNetCore/Middleware/JsonApiMediaType.cs
index d9661abff..cfb2cb8b0 100644
--- a/src/JsonApiDotNetCore/Middleware/JsonApiMediaType.cs
+++ b/src/JsonApiDotNetCore/Middleware/JsonApiMediaType.cs
@@ -25,7 +25,7 @@ public sealed class JsonApiMediaType : IEquatable<JsonApiMediaType>
     public static readonly JsonApiMediaType AtomicOperations = new([JsonApiMediaTypeExtension.AtomicOperations]);
 
     /// <summary>
-    /// Gets the JSON:API media type with the "atomic-operations" extension.
+    /// Gets the JSON:API media type with the "atomic" extension.
     /// </summary>
     public static readonly JsonApiMediaType RelaxedAtomicOperations = new([JsonApiMediaTypeExtension.RelaxedAtomicOperations]);
 
diff --git a/src/JsonApiDotNetCore/Middleware/JsonApiMediaTypeExtension.cs b/src/JsonApiDotNetCore/Middleware/JsonApiMediaTypeExtension.cs
index f35a613dc..6ee7ac10c 100644
--- a/src/JsonApiDotNetCore/Middleware/JsonApiMediaTypeExtension.cs
+++ b/src/JsonApiDotNetCore/Middleware/JsonApiMediaTypeExtension.cs
@@ -9,7 +9,7 @@ namespace JsonApiDotNetCore.Middleware;
 public sealed class JsonApiMediaTypeExtension : IEquatable<JsonApiMediaTypeExtension>
 {
     public static readonly JsonApiMediaTypeExtension AtomicOperations = new("https://jsonapi.org/ext/atomic");
-    public static readonly JsonApiMediaTypeExtension RelaxedAtomicOperations = new("atomic-operations");
+    public static readonly JsonApiMediaTypeExtension RelaxedAtomicOperations = new("atomic");
 
     public string UnescapedValue { get; }
 
diff --git a/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/AcceptHeaderTests.cs b/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/AcceptHeaderTests.cs
index b1f92ffd9..6927e811c 100644
--- a/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/AcceptHeaderTests.cs
+++ b/test/JsonApiDotNetCoreTests/IntegrationTests/ContentNegotiation/AcceptHeaderTests.cs
@@ -121,7 +121,7 @@ public async Task Prefers_JsonApi_with_AtomicOperations_extension_in_Accept_head
             headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default}; profile=some"));
             headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse(JsonApiMediaType.Default.ToString()));
             headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default}; unknown=unexpected"));
-            headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default};EXT=atomic-operations; q=0.8"));
+            headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default};EXT=atomic; q=0.8"));
             headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default};EXT=\"https://jsonapi.org/ext/atomic\"; q=0.2"));
         };
 
@@ -168,7 +168,7 @@ public async Task Prefers_JsonApi_with_relaxed_AtomicOperations_extension_in_Acc
             headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse(JsonApiMediaType.Default.ToString()));
             headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default}; unknown=unexpected"));
             headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default};EXT=\"https://jsonapi.org/ext/atomic\"; q=0.8"));
-            headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default};EXT=atomic-operations; q=0.2"));
+            headers.Accept.Add(MediaTypeWithQualityHeaderValue.Parse($"{JsonApiMediaType.Default};EXT=atomic; q=0.2"));
         };
 
         // Act