Need a start an end date added to Dovecot email sieve

Need a start an end date added to Dovecot email sieve This sieve should only execute if its between 3/31/15 and 4/15/15 Here is my current sieve: require ["vacation"]; # rule:[out-of-country] if true { vacation :days 1 :subject "Re: Out of Office Auto-Reply" text: I'm on vacation from March 31st until April 15th. Contact my collegue at [login to view URL] at [login to view URL] Thanks . ; } See this link, for using the date in a sieve: [login to view URL] [login to view URL] This is a postfix email server, with dovecot as well as dovecot-pigeonhole.