==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.2
- Linux/BSD distribution name and version: Debian GNU/Linux 8.2 (jessie)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- Related log if you're reporting an issue:
====

We made a modification to /etc/postfix/main.cf to apply regexp filtering on headers.
This also required adding a file to /etc/postfix

The question is, will an upgrade of iRedMail or Postfix break our customization or are we safe ?

Thanks,
Gerald.