registered_delivery - clarification

[Iain Dooley]

hi all, i received some clarification back from the carrier: it was only 
the first of a multipart message that got registered_delivery = 1, then 
any subsequent parts of the multipart message had registered_delivery = 0. 
this seems pretty sensible seeing as, from my perspective, a concatenated 
message is really only 1 message.

cheers
iain