Please add an option in the configuration file that allows the server admin to NOT set the SOGo vacation sieve script as the active script. This allows administrators and users to use the include keyword to include the SOGo vacation script into already existing scripts, allowing for better interoperability and coexistence with already existing sieve scripts.

By using the feature outlined here https://datatracker.ietf.org/doc/html/rfc6609 (section 3.2, Control Structure "include") a user would then be able to have their own script reference the SOGo vacation script. An example script could look like this:

  require ["include", "fileinto", "mailbox"];

  include :personal :optional SOGoVacation;             <-- If SOGoVaction script is present, then vacation messages will be sent
  include :global SpamRules;                                      <-- We'll then fall into the spam rules for the organization

  # Users can now create their own rules
  if not address ["To", "CC"] "address@example.com"
  {
      fileinto :create "Low Priority";
  }

  ...

Perhaps allow the server admin to enable/disable SOGo's default behavior with the following configuration example:

  ...
  /* Web Interface */
  SOGoPageTitle = "Example Web Mail";
  SOGoVacationEnabled = YES;
  SOGoForwardEnabled = YES;
  SOGoSieveScriptsEnabled = YES;
  SOGoSieveScriptsActivated = NO;                 <-- This option would prevent script activation; allowing for the script to be included in a user's already existing script.
  SOGoMailAuxiliaryUserAccountsEnabled = YES;
  ...