JUST updated installation to 5.0.16 and Outlook users to 220.127.116.11.
Two users got a meeting change from a Lotus Notes user, ZCO failed to process it and it was delivered as a normal (mostly unreadable) email.
Viewing in webclient, shows as a meeting change like one would expect.
Raw email has an .isc (.ics?) attachment.
Is this a known issue?