In 4.0.1 I was able to make a call to the API similar to the below hich would return only the instances tagged: app=my_app_name
{"tags[0].value"=>"my_app_name", "tags[0].key"=>"app", :command=>"listVirtualMachines", :response=>"json"} (I'm using the cloudstack_helper ruby gem which explains the formatting) However since I have upgraded to 4.1 I now get returned every instance for the same query. Has something changed or am I doing wrong? Thanks Nick