I know this only to be true for once a day (24h i think). After that period the OOF-Notice is sent again from Exchange. So you could send someone a thousand Mails a day and only get a response the first time. But after the Grace-Period of 24 hours you get another OOF-Notice and so on. Isn't that enough? Some people have a attention span of an.... You know what i mean.
EDIT: Ok, checked it on my Test-Setup.. After a few minutes a new OOF-Response is sent from Grommunio.
@EDVMonkey But the once-a-day case would be sufficient right?
I also would like to know how to set at least the 24h's? - Haven't found any options either via
grep -iR /etc/grom*/