Looks like this is probably what was intended.
authorMichael J. Rubinsky <mrubinsk@horde.org>
Fri, 9 Jul 2010 16:34:19 +0000 (12:34 -0400)
committerMichael J. Rubinsky <mrubinsk@horde.org>
Fri, 9 Jul 2010 16:34:19 +0000 (12:34 -0400)
commit3dd61a3ec5c3ff3e8209199afd28abdfd575ba6e
tree541a935fe4e1b4967e53cd7f712b9913e8dfa328
parent7be850ecde5e62cccfa286fb73ad568f75ce2c08
Looks like this is probably what was intended.

Calling calendar/export first while catching the exception will avoid
unwanted notifications when this isn't actually an update operation.
imp/lib/Mime/Viewer/Itip.php