Would be more better if an unfound message is reported as such as opposed to "invalid page format." Would be more nice if an administrative message was generated and inserted documenting "message not available due to: xxx." Depending on xxx, one and software would know the probability of ever "finding" a particular missing message.
--garron
Akin to this, PG Offline is not acquiring "total number of messages," but,
"highest message number."
--garron