diff --git a/specification/compute/resource-manager/Microsoft.Compute/stable/2017-12-01/compute.json b/specification/compute/resource-manager/Microsoft.Compute/stable/2017-12-01/compute.json
index 8573cad19315..3415e284038b 100644
--- a/specification/compute/resource-manager/Microsoft.Compute/stable/2017-12-01/compute.json
+++ b/specification/compute/resource-manager/Microsoft.Compute/stable/2017-12-01/compute.json
@@ -2709,6 +2709,48 @@
           "nextLinkName": "nextLink"
         }
       }
+    },
+	"/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/virtualMachineScaleSets/{vmScaleSetName}/osUpgradeHistory": {
+      "get": {
+        "tags": [
+          "VirtualMachineScaleSets"
+        ],
+        "operationId": "VirtualMachineScaleSets_GetOSUpgradeHistory",
+        "description": "Gets list of OS upgrades on a VM scale set instance.",
+        "parameters": [
+          {
+            "name": "resourceGroupName",
+            "in": "path",
+            "required": true,
+            "type": "string",
+            "description": "The name of the resource group."
+          },
+          {
+            "name": "vmScaleSetName",
+            "in": "path",
+            "required": true,
+            "type": "string",
+            "description": "The name of the VM scale set."
+          },
+          {
+            "$ref": "#/parameters/ApiVersionParameter"
+          },
+          {
+            "$ref": "#/parameters/SubscriptionIdParameter"
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "OK",
+            "schema": {
+              "$ref": "#/definitions/VirtualMachineScaleSetListOSUpgradeHistory"
+            }
+          }
+        },
+        "x-ms-pageable": {
+          "nextLinkName": "nextLink"
+        }
+      }
     },
     "/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.Compute/virtualMachineScaleSets/{vmScaleSetName}/poweroff": {
       "post": {
@@ -7121,6 +7163,116 @@
       ],
       "description": "The Virtual Machine Scale Set List Skus operation response."
     },
+    "UpgradeOperationHistoryStatus": {
+      "properties": {
+        "code": {
+          "type": "string",
+          "readOnly": true,
+          "description": "Code indicating the current status of the upgrade.",
+          "enum": [
+            "RollingForward",
+            "Cancelled",
+            "Completed",
+            "Faulted"
+          ],
+          "x-ms-enum": {
+            "name": "UpgradeState",
+            "modelAsString": false
+          }
+        },
+        "startTime": {
+          "readOnly": true,
+          "type": "string",
+          "format": "date-time",
+          "description": "Start time of the upgrade."
+        },
+        "endTime": {
+          "readOnly": true,
+          "type": "string",
+          "format": "date-time",
+          "description": "End time of the upgrade."
+        }
+      },
+      "description": "Information about the current running state of the overall upgrade."
+    },
+    "UpgradeOperationHistoricalStatusInfoProperties": {
+      "properties": {
+        "runningStatus": {
+          "$ref": "#/definitions/UpgradeOperationHistoryStatus",
+          "readOnly": true,
+          "description": "Information about the overall status of the upgrade operation."
+        },
+        "progress": {
+          "$ref": "#/definitions/RollingUpgradeProgressInfo",
+          "readOnly": true,
+          "description": "Counts of the VM's in each state."
+        },
+        "error": {
+          "$ref": "#/definitions/ApiError",
+          "readOnly": true,
+          "description": "Error Details for this upgrade if there are any."
+        },
+        "startedBy": {
+          "readOnly": true,
+          "type": "string",
+          "description": "Invoker of the Upgrade Operation",
+          "enum": [
+            "Unknown",
+            "User",
+            "Platform"
+          ],
+          "x-ms-enum": {
+            "name": "UpgradeOperationInvoker",
+            "modelAsString": false
+          }
+        },
+        "targetImageReference": {
+          "$ref": "#/definitions/ImageReference",
+          "readOnly": true,
+          "description": "Image Reference details"
+        }
+      },
+      "description": "Describes each OS upgrade on the Virtual Machine Scale Set."
+    },
+    "UpgradeOperationHistoricalStatusInfo": {
+      "properties": {
+        "properties": {
+          "$ref": "#/definitions/UpgradeOperationHistoricalStatusInfoProperties",
+          "readOnly": true,
+          "description": "Information about the properties of the upgrade operation."
+        },
+        "type": {
+          "readOnly": true,
+          "type": "string",
+          "description": "Resource type"
+        },
+        "location": {
+		  "readOnly": true,
+          "type": "string",
+          "description": "Resource location"
+        }
+      },
+      "description": "Virtual Machine Scale Set OS Upgrade History operation response."
+    },
+    "VirtualMachineScaleSetListOSUpgradeHistory": {
+      "properties": {
+        "value": {
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/UpgradeOperationHistoricalStatusInfo"
+          },
+          "description": "The list of OS upgrades performed on the virtual machine scale set."
+        },
+        "nextLink": {
+          "type": "string",
+          "description": "The uri to fetch the next page of OS Upgrade History. Call ListNext() with this to fetch the next page of history of upgrades."
+        }
+      },
+      "required": [
+        "value"
+      ],
+      "description": "List of Virtual Machine Scale Set OS Upgrade History operation response."
+    },
     "VirtualMachineScaleSetVMProperties": {
       "properties": {
         "latestModelApplied": {