on the wiki page

http://www.mirthproject.org/index.ph...=channeleditor

it says under Summary
If the channel receives messages pre-encoded in XML rather than ER7 then ?Channel will receive XML pre-encoded HL7 messages? should be checked.

Mirth 1.7.0 offers no such checkbox. There seems to exist only the Incoming data dropdown which could be set to XML but I doubt that achieves the same thing. Has the functionality been removed or relocated? Among the scripts, "Convert XML to HL7" would not appear a proper selection since it is already HL7 but... :-)