diff --git a/app/controllers/scim_rails/scim_users_controller.rb b/app/controllers/scim_rails/scim_users_controller.rb
index d0acb4fe..88cc8e66 100644
--- a/app/controllers/scim_rails/scim_users_controller.rb
+++ b/app/controllers/scim_rails/scim_users_controller.rb
@@ -140,7 +140,7 @@ def patch_active_param
     end
 
     def valid_patch_operation?(operation)
-      operation["op"].casecmp("replace") &&
+      operation["op"].casecmp?("replace") &&
         operation["value"] &&
         [true, false].include?(operation["value"]["active"])
     end