Line 202 explained: If you look at the STOMP Protocol Docs for [1.0](http://stomp.github.com/stomp-specification-1.0.html#frame-ACK), [1.1](http://stomp.github.com/stomp-specification-1.1.html#SUBSCRIBE_ack_Header), and [1.2](http://stomp.github.com/stomp-specification-1.2.html#SUBSCRIBE_ack_Header) you'll see "If the header is not set, it defaults to auto.".  I've tested it against RabbitMQ with STOMP and successfully connected to 1.0 and 1.1 using 'client', 'auto', and in the case of 1.1 ' client-individual'.  I think more changes to the module would be necessary to test against 1.2.