kolab outlined the vacation script in https://wiki.kolabsys.com/Product:Feature:Vacation and came with a solution, that is not the same than vacation scripts were generated before fom kdepim but actaully is more easy to understand and actually to put untop of other scripts.
The branch dev/sieve_kep14 and dev/vacation (git.kolab.org) make the OOO Dialag feature complete and create the correct scripts add tests etc. To get it upsream we need to implement a migrator routine, than can load the old vacation scripts. They use the same sieve featueres, so we can simply create the new kind of vacation scripts.