Debian系统中的Dovecot套件升级了，一直工作正常，没怎么在意升级的影响。今天在syslog中看到一些告警：

dovecot: config: Warning: NOTE: You can get a new clean config file with: doveconf -n > dovecot-new.conf
dovecot: config: Warning: Obsolete setting in /etc/dovecot/conf.d/auth-system.conf.ext:77: add auth_ prefix to all settings inside auth {} and remove the auth {} section completely

从告警信息看，“/etc/dovecot/conf.d/auth-system.conf.ext”有一些变化，重新修改后可以去除这个告警。比如，原文件中内容为：

auth default {
    socket listen {
        client {
            path = /var/spool/postfix/private/auth-dovecot
            mode = 0660
            user = postfix
            group = postfix
        }
    }
}

新配置修改为以下内容：

service auth {
    unix_listener /var/spool/postfix/private/auth-dovecot {
        mode = 0660
        user = postfix
        group = postfix
    }
}