diff --git a/schemas/2021-09-01-preview/Microsoft.AppPlatform.json b/schemas/2021-09-01-preview/Microsoft.AppPlatform.json
index f6fa160a08..51f77b0c38 100644
--- a/schemas/2021-09-01-preview/Microsoft.AppPlatform.json
+++ b/schemas/2021-09-01-preview/Microsoft.AppPlatform.json
@@ -883,7 +883,7 @@
           "type": "string",
           "description": "The mount path of the persistent disk."
         },
-        "readonly": {
+        "readOnly": {
           "oneOf": [
             {
               "type": "boolean"
@@ -892,7 +892,7 @@
               "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
             }
           ],
-          "description": "Indicates whether the persistent disk is a readonly one."
+          "description": "Indicates whether the persistent disk is a readOnly one."
         }
       },
       "required": [