I rolled up my system last night to the new update. Can confirm it did indeed fix my iOS IMAP access issues. Still had to run my DB/Rabbit fixes as before but that's likely more an issue with my installation.
I did experience issues with delivery of mail following the upgrade - they all sat in the deferred queue with the error
warning: connect to transport private/smtp-amavis: Connection refused
Mails were accepted by the server, but never relayed. I may have introduced this by upgrading to Ubuntu 24.04 in the process.
It turned out to be an issue with the amavis services;
carbonio-mailthreat.service - Carbonio Mail Threat Daemon Loaded: loaded (/usr/lib/systemd/system/carbonio-mailthreat.service; enabled; preset: enabled) Active: active (running) since Wed 2026-04-08 11:33:52 BST; 4min 51s ago Process: 1379862 ExecStartPre=bash -c echo REWRITE amavis | netcat -w 120 localhost 7171; echo REWRITE antispam | netcat -w 120 localhost 7171; /opt/zextras/common/sbin/amavis-mc (code=exited, status=0/SUCCESS) Main PID: 1379881 (/opt/zextras/co) Tasks: 12 (limit: 28741) Memory: 198.1M (peak: 206.1M) CPU: 3.165s CGroup: /system.slice/carbonio-mailthreat.service ├─1379881 "/opt/zextras/common/sbin/amavisd (master)" ├─1379882 /usr/bin/perl -T /opt/zextras/common/sbin/amavis-mc ├─1380307 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380308 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380309 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380310 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380311 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380312 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380313 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380314 "/opt/zextras/common/sbin/amavisd (virgin child)" ├─1380315 "/opt/zextras/common/sbin/amavisd (virgin child)" └─1380316 "/opt/zextras/common/sbin/amavisd (virgin child)" Apr 08 11:34:08 my.server.dns amavis-mc[1379882]: Process [1380643] exited (/opt/zextras/common/sbin/amavis-services snmp-responder) after 0.0 s: exit 2 Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Process [1381418] started: /opt/zextras/common/sbin/amavis-services msg-forwarder Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Process [1381419] started: /opt/zextras/common/sbin/amavis-services childproc-minder Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Process [1381420] started: /opt/zextras/common/sbin/amavis-services snmp-responder Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Process [1381420] exited (/opt/zextras/common/sbin/amavis-services snmp-responder) after 0.0 s: exit 2 Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Exceeded restart count, giving up on (/opt/zextras/common/sbin/amavis-services snmp-responder) Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Process [1381419] exited (/opt/zextras/common/sbin/amavis-services childproc-minder) after 0.0 s: exit 2 Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Exceeded restart count, giving up on (/opt/zextras/common/sbin/amavis-services childproc-minder) Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Process [1381418] exited (/opt/zextras/common/sbin/amavis-services msg-forwarder) after 0.0 s: exit 2 Apr 08 11:34:13 my.server.dns amavis-mc[1379882]: Exceeded restart count, giving up on (/opt/zextras/common/sbin/amavis-services msg-forwarder)
This turned out to be a missing Perl::Syslog package, discoverable by running the following;
zextras@mail1:~ /opt/zextras/common/sbin/amavis-services snmp-responder; echo "snmp-responder rc=$?" Can't locate Unix/Syslog.pm in @INC (you may need to install the Unix::Syslog module) (@INC entries checked: /etc/perl /usr/local/lib/x86_64-linux-gnu/perl/5.38.2 /usr/local/share/perl/5.38.2 /usr/lib/x86_64-linux-gnu/perl5/5.38 /usr/share/perl5 /usr/lib/x86_64-linux-gnu/perl-base /usr/lib/x86_64-linux-gnu/perl/5.38 /usr/share/perl/5.38 /usr/local/lib/site_perl) at /opt/zextras/common/sbin/amavis-services line 56. BEGIN failed--compilation aborted at /opt/zextras/common/sbin/amavis-services line 56. snmp-responder rc=2
Resolvable by running;
root@mail01:/root# apt update && apt install libunix-syslog-perl
Following this, the services were auto restarted and a test now completes ok - all mails are delivered.
zextras@mail01:~ perl -MUnix::Syslog -e 'print "Unix::Syslog OK\n"' Unix::Syslog OK
Hello,
Thanks for the clarification.
We can confirm on our side that after running apt update / apt upgrade, the issue is resolved for iOS IMAP clients.
Even though the Admin UI still shows version 26.3.0, the backend components have been updated (carbonio-mailbox-jar 4.25.2), which matches what you mentioned about the hotfix.
IMAP is now working correctly on iPhone:
- mailbox sync OK
- send/receive OK
- no more empty mailbox issue
In our case, we are using a Proxmox Mail Gateway (PMG) which handles:
- anti-spam
- antivirus
- DKIM (as well as SPF/DMARC enforcement)
So amavis / carbonio-mailthreat is not used on our Carbonio instance. This likely explains why we did not experience the deferred queue issue reported by others.
So overall:
- iOS IMAP issue → fixed after package update
- no need for rollback → confirmed
Thanks for the update and clarification regarding versions.
Bonjour,
Merci pour ces précisions.
Nous confirmons de notre côté qu’après un apt update / apt upgrade, le problème IMAP sur iOS est corrigé.
Même si l’interface admin affiche toujours la version 26.3.0, les composants backend ont bien été mis à jour (carbonio-mailbox-jar 4.25.2), ce qui correspond au correctif évoqué.
L’IMAP fonctionne désormais correctement sur iPhone :
- synchronisation OK
- envoi/réception OK
- plus de boîte vide
Dans notre cas, nous utilisons un Proxmox Mail Gateway (PMG) qui gère :
- l’anti-spam
- l’antivirus
- le DKIM (ainsi que SPF/DMARC)
Ainsi, amavis / carbonio-mailthreat n’est pas utilisé sur notre instance Carbonio, ce qui explique probablement pourquoi nous n’avons pas rencontré le problème de mails bloqués en file d’attente signalé par d’autres.
Conclusion :
- problème iOS IMAP → corrigé après mise à jour des paquets
- pas besoin de rollback → confirmé
Merci pour le retour et les précisions sur les versions.