Final Migration date
As we get closer to the migration and we get ready, we now with confidence can set the actual final date for the migration to the new environment on the new hardware. The migration is going to happen on:
Monday 23rd of March 2026.
All systems are running well and our tests are successful. We are looking forward to using the new system.
On Tuesday 2026-03-03, a number of user accounts on Kolab Now was used to send out large amounts of spam. The spammers didn’t get to send out much mail. Most of it was stopped in the Kolab Now exit filtering, but the spam rating of the mails going out unfortunately was high and caused Microsoft online services, specifically outlook.com, hotmail.com, to add two of the Kolab Now exit IP addresses to their block lists. This caused emails sent to recipients on these services to bounce with messages like:
550 5.7.1 Unfortunately, messages from [212.103.80.154] weren’t sent.
Please contact your Internet service provider since part of their network is on our block list (S3150).
The spammers were identified and stopped, but the damage was done.
It is Friday..
..and it is time to give you a short update on something that we have been working on for a while.
Kolab Now is running on high-end equipment located in a data-center in Bern, Switzerland. It is running the Email- and Groupware services for our customers, such as you. Where as we are aware that Email is ‘mission critical’ for our users, we do what we can to keep the service stable and alive 24/7.
For the sake of transparency we used to report on our interactions with authorities every year. Unfortunately we have missed a few of those reports. Some users missed such updates, and , not only for those users, but also according to our terms of service, and for the sake of transparency, we want to restart this good routine. This post is the transparency reporting for the year 2025.
Last night at 21:50 UTC a large number of client connections hit Kolab Now, which resulted in the IMAP client servers (‘imap.kolabnow.com’) running out of memory. Staff was noted about the issue at 06:00 UTC, and immediately raised the amount of memory for these servers, which brought the issue to an end.
During these ~8 hours users of IMAP clients had issues with unstable connections; some might even have been completely unable to connect.
Mail transport was not impacted. all mails were streaming in and out as they should, and also the webclient (‘https://kolabnow.com/apps’) worked well during the period.
The issue was the unusually large number of incoming client connections. To mitigate the situation and avoid similar issues, the staff has enlarged the memory size on the servers in question, and are now working to improve the monitoring of the service.
We regret the incident and apologize for any inconvenience that this may have caused.
On Sunday 2025-06-15 one of the Kolab now ActiveSync servers were getting overloaded and got stuck on failed jobs. In turn, about 50% of the ActiveSync jobs were failing – leading to some ActiveSync users loosing the connections to Outlook or to their mobile devices.
Yesterday we dealt with a spammer/phisher who specifically targeted the Microsoft outlook.com service (and it’s affiliates). One of the Kolab Now MX servers was listed on the Microsoft throttle list (S3150). This meant that some users saw, that mails sent to recipients at ‘@outlook.com’, ‘@live.com’, ‘@hotmail.com’, and other Microsoft online services was bounced back.
This afternoon earlier today one of the Kolab Now MX servers was listed on the Microsoft block list. This means that some users might have seen, that mails sent to recipients at ‘@outlook.com’, ‘@live.com’, ‘@hotmail.com’, and other Microsoft online services was bounced back with the message that looks something like this:
This is the mail system at host mx.kolabnow.com.I'm sorry to have to inform you that your message could notbe delivered to one or more recipients. It's attached below.For further assistance, please send mail to postmaster.If you do so, please include this problem report. You candelete your own text from the attached returned message.The mail system<some-email@outlook.com>: hostoutlook-com.olc.protection.outlook.com[x.x.x.x] said: 550 5.7.1Unfortunately, messages from [y.y.y.y] weren't sent. Please contactyour Internet service provider since part of their network is on our blocklist (S3150). You can also refer your provider tohttp://mail.live.com/mail/troubleshooting.aspx#errors. [Name=ProtocolFilter Agent][AGT=PFA][MxId=<some long number>][SG2PEPF03345FBECA.apcprd05.prod.outlook.com 2025-02-13T<timestamp>Z<another long number>] (in reply to MAIL FROM command)
Although the listing was fast discovered, Microsoft was contacted and the listing is reversed as soon as it is possible, it took a while. At this time emails should be delivered to the Microsoft online services.
A few users has misinterpreted the symptoms with error messages from missing the DKIM changes made on Monday (please read this blog post from December 2024 and the follow ups). If you are a group manager, then please make sure that you have the new DKIM related CNAMES added to your DNS zone.
If you have any questions or concerns in this context, then please contact support.
On December 20’th 2024 we announced a change to the DKIM configuration on Kolab Now. The announcement described actions needed for users with private domains. We recommended that group managers (the owners of private domains) set the following CNAMEs (both of them) in the DNS of their private domain:
dkim1._domainkey CNAME dkim1._domainkey.kolabnow.com.
dkim2._domainkey CNAME dkim2._domainkey.kolabnow.com.
We also said in the announcement, that we would provide the actual update top the system in the end of January. Unfortunately the snow in the Swiss alps was so wonderful in the end of January, that our techies got a bit delayed.
However, it has now come so far that we announce a service window on:
Monday February 10’th, 2025 @ 08:00 UTC.
The Service window will last for an hour, within which users might see a small bump in the performance.
If you are the owner of a private domain and you have not yet added the CNAME records to your domain, then your outgoing emails might be refused by the recipient servers after the change.
We will keep you up to date with the progress of the work via updates to this post.
– 2025-02-10 @ 07:59 UTC: The service window is now open and the work is in progress. As written, you should not see any big impact.
– 2025-02-10 @ 08:45 UTC: The change has been implemented, and the service window is done. The new domain alignment is tested and seems to be working as expected. If you have any problems with your private domain, then please contact support.
The Kolab Now development team has been working on updating Roundcube to version 1.6 on the platform for a while, and we are finally ready to push it. Therefore we hereby announce a service window for:
Wednesday 2025-01-22 @ 08:00 UTC (09:00 CEST)
The service window will last for an hour. Users can keep working, but there may be brief webmail interruptions during the period.
Users using the old ‘Larry’ skin might experience some short-comings and problems with that skin. Users with such issues can switch to use one of the two Kolab Now skins (Settings -> Preferences -> User interface -> Interface skin).
If you are one such user and you really want to make use of the old ‘Larry’ skin, then please contact support.
In fact, Please contact support with any questions or concerns in this context.
