diff --git a/runtimes/runtimes.go b/runtimes/runtimes.go
index 30e1bc066..3b5cc8d01 100644
--- a/runtimes/runtimes.go
+++ b/runtimes/runtimes.go
@@ -468,7 +468,7 @@ var RUNTIME_DETAILS = []byte(`{
         "dotnet": [
             {
                 "kind": "dotnet:2.2",
-                "default": true,
+                "default": false,
                 "deprecated": false,
                 "requireMain": true,
                 "image": {
@@ -480,6 +480,21 @@ var RUNTIME_DETAILS = []byte(`{
                     "attachmentName": "codefile",
                     "attachmentType": "text/plain"
                 }
+            },	    
+            {
+                "kind": "dotnet:3.1",
+                "default": true,
+                "deprecated": false,
+                "requireMain": true,
+                "image": {
+                    "prefix": "openwhisk",
+                    "name": "action-dotnet-v3.1",
+                    "tag": "nightly"
+                },
+                "attached": {
+                    "attachmentName": "codefile",
+                    "attachmentType": "text/plain"
+                }
             }
         ],
         "ballerina": [