> Another possibility would be to use %s, e.g.:
> 
> passdb {
>   driver = passwd-file
>   master = yes
>   args = /etc/dovecot/master.%s
> }
> 
> Then use master.sieve file.
I guess that should read
passdb passwd-file {
  master = yes
  args = .../master.%s
}
instead. Thanks, seems to work great.