I have release a new bundle for Roundcube 0.6-beta
Calendar Plugin:
(*) Re-configuration and database adjustments are required:
(**) 'events', 'events_cache', 'events_caldav' tables new fields (MySQL example):
`reminder` int(10) DEFAULT NULL,
`reminderservice` text,
`remindermailto` text,
`remindersent` int(10) DEFAULT NULL,
(**) new table 'reminders'