querylog message format - XX vs XX+

[Geoff Steer]

I'm preparing to install a new DNS server running BIND 8.2.1 on Redhat
6.0 to replace an older server (BIND 8.1.2 ) 
In testing the new server, I've turned on query logging. The entries
that are generated on the new server are of the form:

XX+/137.172.211.9/falgate.fujitsu.com.au/A

Where the same query via the old server produces:

XX /137.172.211.9/falgate.fujitsu.com.au/A

I've stopped the name servers in case it was something cached. Both name
servers are primary for the fujitsu.com.au zone.
I've been throught 'DNS and Bind' (even searched the CD version) but I
can't find anything that tells me the significance of the + after the
initial XX.

I'm not familiar enough with the source code to find this, hence my
question.

Regards
Geoff Steer
Fujitsu Australia Ltd.