Case sensitivity in :addresses in sieve vacation scripts

Hi,

I have recently updated from Dovecot 2.2 to 2.3. Since I have noticed that vacation responses from sieve are not working the same anymore. For example, my sieve script looks like this:

vacation :days 1 :addresses ["Kippels@hhu.de","julian.kippels@hhu.de"]

it used to be that I got a vacation response if I sent a mail to kippels@hhu.de and Kippels@hhu.de. Now I only get a response for Kippels@hhu.de, not for kippels@hhu.de. I cant say for sure, but I suppose this behaviour changed with the update. If not, why could this have happened? And in any case, how can I enable case insensitivity?

Thanks Julian