diff --git a/specification/signalr/resource-manager/Microsoft.SignalRService/preview/2020-07-01-preview/signalr.json b/specification/signalr/resource-manager/Microsoft.SignalRService/preview/2020-07-01-preview/signalr.json
index 39a47b3a804b..49555b69da3f 100644
--- a/specification/signalr/resource-manager/Microsoft.SignalRService/preview/2020-07-01-preview/signalr.json
+++ b/specification/signalr/resource-manager/Microsoft.SignalRService/preview/2020-07-01-preview/signalr.json
@@ -1142,12 +1142,14 @@
           "description": "Optional tier of this particular SKU. 'Standard' or 'Free'. \r\n\r\n`Basic` is deprecated, use `Standard` instead."
         },
         "size": {
-          "description": "Optional string. For future use.",
-          "type": "string"
+          "description": "Not used. Retained for future use.",
+          "type": "string",
+          "readOnly": true
         },
         "family": {
-          "description": "Optional string. For future use.",
-          "type": "string"
+          "description": "Not used. Retained for future use.",
+          "type": "string",
+          "readOnly": true
         },
         "capacity": {
           "format": "int32",
diff --git a/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_CreateOrUpdate.json b/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_CreateOrUpdate.json
index 3eb1a78ba38b..02bb608ec5d9 100644
--- a/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_CreateOrUpdate.json
+++ b/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_CreateOrUpdate.json
@@ -7,7 +7,6 @@
         "capacity": 1
       },
       "properties": {
-        "hostNamePrefix": null,
         "features": [
           {
             "flag": "ServiceMode",
diff --git a/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_Update.json b/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_Update.json
index 29a1ef2fd73f..9dbf0ad1c5f3 100644
--- a/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_Update.json
+++ b/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/examples/SignalR_Update.json
@@ -7,7 +7,6 @@
         "capacity": 1
       },
       "properties": {
-        "hostNamePrefix": null,
         "features": [
           {
             "flag": "ServiceMode",
diff --git a/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/signalr.json b/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/signalr.json
index 844d2f52801c..540d82e0e9a7 100644
--- a/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/signalr.json
+++ b/specification/signalr/resource-manager/Microsoft.SignalRService/stable/2020-05-01/signalr.json
@@ -1138,12 +1138,14 @@
           "description": "Optional tier of this particular SKU. 'Standard' or 'Free'. \r\n\r\n`Basic` is deprecated, use `Standard` instead."
         },
         "size": {
-          "description": "Optional string. For future use.",
-          "type": "string"
+          "description": "Not used. Retained for future use.",
+          "type": "string",
+          "readOnly": true
         },
         "family": {
-          "description": "Optional string. For future use.",
-          "type": "string"
+          "description": "Not used. Retained for future use.",
+          "type": "string",
+          "readOnly": true
         },
         "capacity": {
           "format": "int32",
@@ -1242,7 +1244,8 @@
       "properties": {
         "hostNamePrefix": {
           "description": "Prefix for the hostName of the SignalR service. Retained for future use.\r\nThe hostname will be of format: <hostNamePrefix>.service.signalr.net.",
-          "type": "string"
+          "type": "string",
+          "readOnly": true
         },
         "features": {
           "description": "List of SignalR featureFlags. e.g. ServiceMode.\r\n\r\nFeatureFlags that are not included in the parameters for the update operation will not be modified.\r\nAnd the response will only include featureFlags that are explicitly set. \r\nWhen a featureFlag is not explicitly set, SignalR service will use its globally default value. \r\nBut keep in mind, the default value doesn't mean \"false\". It varies in terms of different FeatureFlags.",