diff --git a/scim2_server/resources/default-schemas.json b/scim2_server/resources/default-schemas.json
index 710baab..ca7f164 100644
--- a/scim2_server/resources/default-schemas.json
+++ b/scim2_server/resources/default-schemas.json
@@ -520,6 +520,15 @@
                         "mutability": "readWrite",
                         "returned": "default",
                         "uniqueness": "none"
+                    },
+                    {
+                        "name": "primary",
+                        "type": "boolean",
+                        "multiValued": false,
+                        "description": "A Boolean value indicating the 'primary' or preferred attribute value for this attribute.  The primary attribute value 'true' MUST appear no more than once.",
+                        "required": false,
+                        "mutability": "readWrite",
+                        "returned": "default"
                     }
                 ],
                 "mutability": "readWrite",