One of the last parameters you can set for the external component/domain is a protocol which should be used for the connection. At the moment the Tigase server supports two protocols defined in XEP-0114 and XEP-0225 and possibly in the future it may support more.
You don’t have to specify a protocol if you setup a connection in 'listen' mode as the server automatically detects a protocol which is used in incoming connections.
You can, however specify the protocol which is used for outgoing connections. You have to add one more parameter to the connection string. There are two possibilities:
An example configuration with protocol specified:
--comp-name-1 = ext --comp-class-1 = tigase.server.ext.ComponentProtocol --external = devel.tigase.org:mucsecret:connect:5270:muc.devel.tigase.org:accept, \ devel.tigase.org:pubsub_pass:connect:5270:pubsub.devel.tigase.org:client