diff --git a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2019-05-01-preview/appplatform.json b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2019-05-01-preview/appplatform.json
index 63d5c1ac19c4..4bca895a613e 100644
--- a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2019-05-01-preview/appplatform.json
+++ b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2019-05-01-preview/appplatform.json
@@ -3660,6 +3660,10 @@
           "items": {
             "$ref": "#/definitions/MetricDimension"
           }
+        },
+        "sourceMdmNamespace": {
+          "description": "Name of the MDM namespace. Optional.",
+          "type": "string"
         }
       }
     },
diff --git a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2020-11-01-preview/appplatform.json b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2020-11-01-preview/appplatform.json
index aa9615cff9b6..678926090b77 100644
--- a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2020-11-01-preview/appplatform.json
+++ b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2020-11-01-preview/appplatform.json
@@ -4244,6 +4244,10 @@
           "items": {
             "$ref": "#/definitions/MetricDimension"
           }
+        },
+        "sourceMdmNamespace": {
+          "description": "Name of the MDM namespace. Optional.",
+          "type": "string"
         }
       }
     },
diff --git a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2021-06-01-preview/appplatform.json b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2021-06-01-preview/appplatform.json
index 0fa858b7ca6e..3174ae39cad0 100644
--- a/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2021-06-01-preview/appplatform.json
+++ b/specification/appplatform/resource-manager/Microsoft.AppPlatform/preview/2021-06-01-preview/appplatform.json
@@ -4324,6 +4324,10 @@
           "items": {
             "$ref": "#/definitions/MetricDimension"
           }
+        },
+        "sourceMdmNamespace": {
+          "description": "Name of the MDM namespace. Optional.",
+          "type": "string"
         }
       }
     },
diff --git a/specification/appplatform/resource-manager/Microsoft.AppPlatform/stable/2020-07-01/appplatform.json b/specification/appplatform/resource-manager/Microsoft.AppPlatform/stable/2020-07-01/appplatform.json
index d0d132d16f10..d18821cea9f8 100644
--- a/specification/appplatform/resource-manager/Microsoft.AppPlatform/stable/2020-07-01/appplatform.json
+++ b/specification/appplatform/resource-manager/Microsoft.AppPlatform/stable/2020-07-01/appplatform.json
@@ -4215,6 +4215,10 @@
           "items": {
             "$ref": "#/definitions/MetricDimension"
           }
+        },
+        "sourceMdmNamespace": {
+          "description": "Name of the MDM namespace. Optional.",
+          "type": "string"
         }
       }
     },