diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CheckNameAvailability.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CheckNameAvailability.json
index be3e48de33fb..daa814b1499f 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CheckNameAvailability.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CheckNameAvailability.json
@@ -3,15 +3,30 @@
     "subscriptionId": "00000000-0000-0000-0000-000000000000",
     "api-version": "2018-09-01",
     "operationInputs": {
-      "name": "myIoTCentralApp"
+      "name": "myIoTCentralApp",
+      "type": "IoTApps"
     }
   },
   "responses": {
     "200": {
-      "headers": {},
+      "description": "Returns information about resource name availability",
+      "headers": {
+        "code": "200"
+      },
       "body": {
         "nameAvailable": true
       }
+    },
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {},
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
+      }
     }
   }
 }
\ No newline at end of file
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CheckSubdomainAvailability.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CheckSubdomainAvailability.json
new file mode 100644
index 000000000000..1d7bac270480
--- /dev/null
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CheckSubdomainAvailability.json
@@ -0,0 +1,32 @@
+{
+  "parameters": {
+    "subscriptionId": "00000000-0000-0000-0000-000000000000",
+    "api-version": "2018-09-01",
+    "operationInputs": {
+      "name": "myIoTCentralApp",
+      "type": "IoTApps"
+    }
+  },
+  "responses": {
+    "200": {
+      "description": "Returns information about resource subdomain availability",
+      "headers": {
+          "code": "200"
+      },
+      "body": {
+        "nameAvailable": true
+      }
+    },
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {},
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
+      }
+    }
+  }
+}
\ No newline at end of file
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CreateOrUpdate.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CreateOrUpdate.json
index 08779ed2c704..8416e881acd2 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CreateOrUpdate.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_CreateOrUpdate.json
@@ -16,12 +16,18 @@
   },
   "responses": {
     "200": {
-      "headers": {},
+      "header": {
+        "code": "200",
+        "message": "OK"
+      },
       "body": {
         "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/resRg/providers/Microsoft.IoTCentral/IoTApps/myIoTCentralApp",
         "name": "myIoTCentralApp",
         "type": "Microsoft.IoTCentral/IoTApps",
         "location": "westus",
+        "tags": {
+          "key": "value"
+        },
         "properties": {
           "applicationId": "6ebd8fd3-6e34-419e-908f-9be61ec6f6d6",
           "displayName": "My IoT Central App 2",
@@ -34,12 +40,19 @@
       }
     },
     "201": {
-      "headers": {},
+      "headers": {
+        "code": "201",
+        "message": "Created",
+        "target": "ResourceHandler.ExecutePutRequest"
+      },
       "body": {
         "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/resRg/providers/Microsoft.IoTCentral/IoTApps/myIoTCentralApp",
         "name": "myIoTCentralApp",
         "type": "Microsoft.IoTCentral/IoTApps",
         "location": "westus",
+        "tags": {
+          "key": "value"
+        },
         "properties": {
           "applicationId": "6ebd8fd3-6e34-419e-908f-9be61ec6f6d6",
           "displayName": "My IoT Central App",
@@ -51,6 +64,17 @@
         }
       }
     },
-    "202": {}
+    "202": {},
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {},
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
+      }
+    }
   }
 }
\ No newline at end of file
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Delete.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Delete.json
index ea4d3fd59aa4..6cadd187fed0 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Delete.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Delete.json
@@ -6,8 +6,28 @@
     "api-version": "2018-09-01"
   },
   "responses": {
-    "200": {},
+    "200": {
+      "header": {
+        "code": "200",
+        "message": "OK",
+        "target": "ResourceHandler.ExecuteDeleteRequest"
+      }
+    },
     "202": {},
-    "204": {}
+    "204": {},
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {
+        "message": "Created",
+        "code": "200"
+      },
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
+      }
+    }
   }
 }
\ No newline at end of file
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Get.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Get.json
index 738c93b1e7da..fe6000962120 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Get.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Get.json
@@ -7,12 +7,18 @@
   },
   "responses": {
     "200": {
-      "headers": {},
+      "description": "Returns the application details",
+      "headers": {
+        "code": "200"
+      },
       "body": {
         "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/resRg/providers/Microsoft.IoTCentral/IoTApps/myIoTCentralApp",
         "location": "westus",
         "type": "Microsoft.IoTCentral/IoTApps",
         "name": "myIoTCentralApp",
+        "tags": {
+          "key": "value"
+        },
         "properties": {
           "applicationId": "6ebd8fd3-6e34-419e-908f-9be61ec6f6d6",
           "displayName": "My IoT Central App",
@@ -23,6 +29,17 @@
           "name": "F1"
         }
       }
+    }, 
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {},
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
+      }
     }
   }
 }
\ No newline at end of file
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListByResourceGroup.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListByResourceGroup.json
index 63d9d00a43c9..d3321d10ea59 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListByResourceGroup.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListByResourceGroup.json
@@ -6,7 +6,9 @@
   },
   "responses": {
     "200": {
-      "headers": {},
+      "headers": {
+        "code": "200"
+      },
       "body": {
         "value": [
           {
@@ -14,6 +16,9 @@
             "location": "westus",
             "type": "Microsoft.IoTCentral/IoTApps",
             "name": "myIoTCentralApp",
+            "tags": {
+              "key": "value"
+            },
             "properties": {
               "applicationId": "6ebd8fd3-6e34-419e-908f-9be61ec6f6d6",
               "displayName": "My IoT Central App",
@@ -24,7 +29,19 @@
               "name": "F1"
             }
           }
-        ]
+        ],
+        "nextLink": null
+      }
+    },
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {},
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
       }
     }
   }
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListBySubscription.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListBySubscription.json
index a74d0fe95317..6392fc8ad6bb 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListBySubscription.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_ListBySubscription.json
@@ -5,7 +5,9 @@
   },
   "responses": {
     "200": {
-      "headers": {},
+      "headers": {
+        "code": "200"
+      },
       "body": {
         "value": [
           {
@@ -13,6 +15,9 @@
             "location": "westus",
             "type": "Microsoft.IoTCentral/IoTApps",
             "name": "myIoTCentralApp",
+            "tags": {
+              "key": "value"
+            },
             "properties": {
               "applicationId": "6ebd8fd3-6e34-419e-908f-9be61ec6f6d6",
               "displayName": "My IoT Central App",
@@ -23,7 +28,19 @@
               "name": "F1"
             }
           }
-        ]
+        ],
+        "nextLink": null
+      },
+      "default": {
+        "description": "Error message returned for an unexpected response",
+        "headers": {},
+        "body": {
+          "error": {
+            "code": "Error code",
+            "message": "Error message",
+            "target": "Error target"
+          }
+        }
       }
     }
   }
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Update.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Update.json
index cd7ef27c0f02..431b094216d8 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Update.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Apps_Update.json
@@ -10,12 +10,19 @@
   },
   "responses": {
     "200": {
-      "headers": {},
+      "headers": {
+        "code": "200",
+        "message": "OK",
+        "target": "ResourceHandler.ExecutePatchRequest"
+      },
       "body": {
         "id": "/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/resRg/providers/Microsoft.IoTCentral/IoTApps/myIoTCentralApp",
         "location": "westus",
         "type": "Microsoft.IoTCentral/IoTApps",
         "name": "myIoTCentralApp",
+        "tags": {
+          "key": "value"
+        },
         "properties": {
           "applicationId": "6ebd8fd3-6e34-419e-908f-9be61ec6f6d6",
           "displayName": "My IoT Central App 2",
@@ -27,6 +34,17 @@
         }
       }
     },
-    "202": {}
+    "202": {},
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {},
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
+      }
+    }
   }
 }
\ No newline at end of file
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Operations_List.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Operations_List.json
index 81eac53da335..121472301642 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Operations_List.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/examples/Operations_List.json
@@ -4,7 +4,9 @@
   },
   "responses": {
     "200": {
-      "headers": {},
+      "headers": {
+        "code": "200"
+      },
       "body": {
         "value": [
           {
@@ -52,7 +54,19 @@
               "description": "Gets all the available operations on IoT Central Applications"
             }
           }
-        ]
+        ],
+        "nextLink": null
+      }
+    },
+    "default": {
+      "description": "Error message returned for an unexpected response",
+      "headers": {},
+      "body": {
+        "error": {
+          "code": "Error code",
+          "message": "Error message",
+          "target": "Error target"
+        }
       }
     }
   }
diff --git a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/iotcentral.json b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/iotcentral.json
index 88b9479e2e79..52269cc2dafc 100644
--- a/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/iotcentral.json
+++ b/specification/iotcentral/resource-manager/Microsoft.IoTCentral/stable/2018-09-01/iotcentral.json
@@ -351,7 +351,53 @@
           "200": {
             "description": "This is a synchronous operation. The body contains a JSON-serialized response that specifies whether the IoT Central application name is available. If the name is not available, the body contains the reason.",
             "schema": {
-              "$ref": "#/definitions/AppNameAvailabilityInfo"
+              "$ref": "#/definitions/AppAvailabilityInfo"
+            }
+          },
+          "default": {
+            "description": "DefaultErrorResponse",
+            "schema": {
+              "$ref": "#/definitions/ErrorDetails"
+            }
+          }
+        },
+        "deprecated": false
+      }
+    },
+    "/subscriptions/{subscriptionId}/providers/Microsoft.IoTCentral/checkSubdomainAvailability": {
+      "post": {
+        "tags": [
+          "Apps"
+        ],
+        "description": "Check if an IoT Central application subdomain is available.",
+        "operationId": "Apps_CheckSubdomainAvailability",
+        "x-ms-examples": {
+          "Apps_SubdomainAvailability": {
+            "$ref": "./examples/Apps_CheckSubdomainAvailability.json"
+          }
+        },
+        "parameters": [
+          {
+            "$ref": "#/parameters/api-version"
+          },
+          {
+            "$ref": "#/parameters/subscriptionId"
+          },
+          {
+            "name": "operationInputs",
+            "in": "body",
+            "description": "Set the name parameter in the OperationInputs structure to the subdomain of the IoT Central application to check.",
+            "required": true,
+            "schema": {
+              "$ref": "#/definitions/OperationInputs"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "This is a synchronous operation. The body contains a JSON-serialized response that specifies whether the IoT Central application subdomain is available. If the subdomain is not available, the body contains the reason.",
+            "schema": {
+              "$ref": "#/definitions/AppAvailabilityInfo"
             }
           },
           "default": {
@@ -537,22 +583,38 @@
     },
     "ErrorDetails": {
       "description": "Error details.",
+      "properties": {
+        "error": {
+          "x-ms-client-flatten": true,
+          "$ref": "#/definitions/ErrorResponseBody"
+        }
+      }
+    },
+    "ErrorResponseBody": {
+      "description": "Details of error response.",
       "type": "object",
       "properties": {
         "code": {
-          "description": "The error code.",
           "type": "string",
+          "description": "The error code.",
           "readOnly": true
         },
         "message": {
-          "description": "The error message.",
           "type": "string",
+          "description": "The error message.",
           "readOnly": true
         },
         "target": {
-          "description": "The target of the particular error.",
           "type": "string",
+          "description": "The target of the particular error.",
           "readOnly": true
+        },
+        "details": {
+          "type": "array",
+          "description": "A list of additional details about the error.",
+          "items": {
+            "$ref": "#/definitions/ErrorResponseBody"
+          }
         }
       }
     },
@@ -638,15 +700,21 @@
       "properties": {
         "name": {
           "description": "The name of the IoT Central application instance to check.",
-          "type": "string"
+          "type": "string",
+          "pattern": "^[a-z0-9-]{1,63}$"
+        },
+        "type": {
+          "description": "The type of the IoT Central resource to query.",
+          "type": "string",
+          "default": "IoTApps"
         }
       },
       "required": [
         "name"
       ]
     },
-    "AppNameAvailabilityInfo": {
-      "description": "The properties indicating whether a given IoT Central application name is available.",
+    "AppAvailabilityInfo": {
+      "description": "The properties indicating whether a given IoT Central application name or subdomain is available.",
       "type": "object",
       "properties": {
         "nameAvailable": {
@@ -656,20 +724,13 @@
         },
         "reason": {
           "description": "The reason for unavailability.",
-          "enum": [
-            "Invalid",
-            "AlreadyExists"
-          ],
           "type": "string",
-          "readOnly": true,
-          "x-ms-enum": {
-            "name": "AppNameUnavailabilityReason",
-            "modelAsString": false
-          }
+          "readOnly": true
         },
         "message": {
           "description": "The detailed reason message.",
-          "type": "string"
+          "type": "string",
+          "readOnly": true
         }
       }
     }