[Dovecot] quota warning for fs quota

Hello,

I configured my Dovecot to use filesystem (fs) quota. It works fine, the correct free/used space and percentage is being shown to the client. However, the warning feature doesn't seem to work, no mail is being sent, although executing the script standalone works fine.

Is quota warning for fs quota supported? I use Dovecot 1.0.10 (Ubuntu package).

Thanks, Florian