==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 1.8.6
- Deployed with iRedMail Easy or the downloadable installer? Downloadable
- Linux/BSD distribution name and version: Debian Trixie 13 (Proxmox CT)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): PGSQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? N
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

As postmaster in Roundcube webmail, I create a new folder and then a filter to move messages with subject 'Test' into said folder.  Send such an email and delivered to Inbox, not moved into folder.

Dovecot Logs with log_debug = category=sieve show:

Warning: sieve: storage personal: file: Active sieve script symlink /var/vmail/vmail1/nzgeeks.com/p/o/s/postmaster/sieve/dovecot.sieve is no symlink.

Identical (fresh install) and steps with Debian 12; filter delivers message to folder as expected.

Background: I've been happilly using iRedMail for several years on a Debian 12 Proxmox CT and decided to build a new Debian 13 CT and move only Maildir's across.  Was dismayed to find my newly recreated filters no longer worked the new iRedMail server.  Got fed up troubleshooting so went back to basics with new Deb12 and Deb13 containers and installing latest iRedMail on both to discover it might not have been me after all.

Thanks