==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.8
- Linux/BSD distribution name and version: Centos 7
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): LDAP AD Windows server 2016
- Web server (Apache or Nginx):Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

It is known than user's quota can become established by default in Dovecot but general, I have configured it of the following way:

plugin {
    # Quota configuration.
    # Reference: http://wiki2.dovecot.org/Quota/Configuration
    quota = dict:user::proxy::quotadict
       
    # Set default quota rule if no quota returned from SQL/LDAP query.
    quota_rule = *:storage=200m
    quota_rule2 = *:messages=3000
    quota_rule3 = Trash:storage=+10%
    quota_rule4 = Junk:ignore

Now then, but I have users' group that has to utilize a different quota to this first configured, and I want to establish one to 5 specific users different. The question is, as quotas personalized to determined users can be configured in dovecot.

I use Integration Activate Directory with Windows Server 2016.