With 5.5.1 sogo-tool update-autoreply now removes an autoreply as soon as a start date is given. It doesn't matter if there is a timeline or not. Each run of sogo-tool update-autoreply removes it. I can no longer configure a vacation message in advance.
I have now deactivated sogo-tool update-autoreply this cron job. The sieve script does hist job without this.

Even if the Sieve script is updated, the vacation message is still visible from the Web interface. You can still configure your auto-reply in advance.

One possible improvement would be to avoid updating the Sieve script when the server supports the date extension.

I loved it when, after running update-autoreply at the end of the out-of-office period, the out-of-office message was completely disabled. If update-autoreply is not running and you log into the WebUI, it still shows that an out-of-office message is active. On the one hand, this is true, but the notification will no longer be sent after the end date.