diff --git a/src/Stripe.Tests.XUnit/subscriptions/_fixture.cs b/src/Stripe.Tests.XUnit/subscriptions/_fixture.cs
index cce7a0ab77..e02239b1bc 100755
--- a/src/Stripe.Tests.XUnit/subscriptions/_fixture.cs
+++ b/src/Stripe.Tests.XUnit/subscriptions/_fixture.cs
@@ -37,7 +37,12 @@ public subscription_fixture()
                 Items = new List<StripeSubscriptionItemUpdateOption>
                 {
                     new StripeSubscriptionItemUpdateOption { Id = Subscription.Items.Data[0].Id, Deleted = true },
-                    new StripeSubscriptionItemUpdateOption { Id = Subscription.Items.Data[1].Id, Quantity = 5 }
+                    new StripeSubscriptionItemUpdateOption
+                    {
+                        Id = Subscription.Items.Data[1].Id,
+                        Quantity = 5,
+                        Metadata = new Dictionary<string, string>{ {"key", "value"} }
+                    }
                 }
             };
 
diff --git a/src/Stripe.Tests.XUnit/subscriptions/creating_and_updating_subscriptions.cs b/src/Stripe.Tests.XUnit/subscriptions/creating_and_updating_subscriptions.cs
index 92fce3a73e..d342c2c83c 100755
--- a/src/Stripe.Tests.XUnit/subscriptions/creating_and_updating_subscriptions.cs
+++ b/src/Stripe.Tests.XUnit/subscriptions/creating_and_updating_subscriptions.cs
@@ -57,6 +57,18 @@ public void updated_has_right_quantity()
             fixture.SubscriptionUpdated.Items.Data[0].Quantity.Should().Be(fixture.SubscriptionUpdateOptions.Items[1].Quantity);
         }
 
+        [Fact]
+        public void updated_has_metadata_keys()
+        {
+            fixture.SubscriptionUpdated.Items.Data[0].Metadata.Should().ContainKeys(fixture.SubscriptionUpdateOptions.Items[1].Metadata.Keys);
+        }
+
+        [Fact]
+        public void updated_has_metadata_values()
+        {
+            fixture.SubscriptionUpdated.Items.Data[0].Metadata.Should().ContainValues(fixture.SubscriptionUpdateOptions.Items[1].Metadata.Values);
+        }
+
         [Fact]
         public void ended_should_not_be_null()
         {
diff --git a/src/Stripe.net/Infrastructure/Middleware/ParserPlugin/SubscriptionItemUpdatedPlugin.cs b/src/Stripe.net/Infrastructure/Middleware/ParserPlugin/SubscriptionItemUpdatedPlugin.cs
index a670ad958b..193a81a7a5 100755
--- a/src/Stripe.net/Infrastructure/Middleware/ParserPlugin/SubscriptionItemUpdatedPlugin.cs
+++ b/src/Stripe.net/Infrastructure/Middleware/ParserPlugin/SubscriptionItemUpdatedPlugin.cs
@@ -27,9 +27,9 @@ public bool Parse(ref string requestString, JsonPropertyAttribute attribute, Pro
                     // it must have a json attribute matching stripe's key, and only one
                     var attr = prop.GetCustomAttributes<JsonPropertyAttribute>().SingleOrDefault();
                     if (attr == null) continue;
-
-                    RequestStringBuilder.ApplyParameterToRequestString(ref requestString,
-                        $"items[{itemIndex}][{attr.PropertyName}]", value.ToString());
+                    // a JsonPropertyAttribute is required to supply a property name to parser plugins.
+                    var indexedItemAttribute = new JsonPropertyAttribute($"items[{itemIndex}][{attr.PropertyName}]");
+                    RequestStringBuilder.ProcessPlugins(ref requestString, indexedItemAttribute, prop, value, propertyParent);
                 }
 
                 itemIndex++;