Good afternoon,

We have adapted and make some modifications to Kolab calendar's plugin, in order to work with recent versions of Roundcube (1.3.X). Our plugin too, supports scheduling properly as we adapted that code from Kolab's plugin. Would you be interested in it?. At my company Sarenet, have given me permission for donating it to Roundcube. Would you like to have it?. Where could I send?.

Cheers!