September 2025: Transition to Zimbra 10

We are excited to announce the upcoming upgrade and migration of our Zimbra email servers to Zimbra 10, with exciting new features to enhance your email experience.

Version 10.1 is the latest major release of the Zimbra email and collaboration platform, bringing a host of new features and improvements. This upgrade focuses on enhancing usability, performance, and security, ensuring that you have a more efficient and enjoyable experience.

At A Glance

Migration Starts Soon: Mailbox migrations to Zimbra 10 will start mid-September and will be fully complete by the end of the month.

Minimal Disruption: The migration will likely go unnoticed by most users, although mobile and IMAP devices will need to re-sync. See further below for recommendations to minimize sync inconvenience if you have a large mailbox.

HIS Zimbra Webmail will remain available at all time:
Your mailbox will keep the familiatr “Classic” UI after the move.
Your day-to-day use of HIS Zimbra webmail during the migration should remain unaffected.

Freeze period: There will be about a week mid-September while we are copying the data over to the new Zimbra servers when we will not be able to add any new Zimbra email account. Thank you for your understanding and patience.

At the time of the switchover (TBD): There might be a few minutes interruption while your mailbox is locked and connections are switched to the new servers. This process is designed to be smooth and should not cause any noticeable disruption and you will be able to use your mailbox as usual.
The most recent messages will be copied to your email account overnight within a few hours.
Note: If you happen to be logged in to webmail during the switch, you’ll see an update notice once this takes place. Click “Yes,” and after a few moments, you’ll be back in your webmail.

Email apps:
The transition will be smooth and you should not have to change anything to your current settings. All credentials will th moved to the new servers.
However, most mobile and email apps will re-sync the content of the mailbox after the migration.
See below hoe you can minimize it if you have a large mailbox.

Outlook Connector:
You will have to download and install the Zimbra 10 version of the Outlook Connector.
It will be available at: (TBD)

If you have a large mailbox:
Minimize the time it will take to sync your messages once switched over to Zimbra 10 by shortening the number of days your email app syncs mail for:

• Apple iPhone or iPad
• Outlook App

What's in store with Zimbra 10?

Here’s a rundown of what’s changing and how it will benefit you:

Zimbra Apple iPhone/iPad App

Zimbra 10 has a new iPhone/iPad App, available in the App Store. This app allows you to access the full suite of Zimbra Collaboration options, including emails, calendar, contacts, and documents, all in one place. Enjoy a seamless experience on your mobile device, bypassing the need to use Apple’s default mail app.

Offline mode in Webmail

Both the Classic and Modern Web Clients now support Offline Mode. This allows you to manage and compose mail, contacts, and appointments when you are offline. The changes will sync when you are back online, making it perfect for staying productive at any time.

Modern Web Client
The switch to Zimbra 10 introduces the availability of a Modern Web Client, which offers a clean, streamlined interface that aims to improve your productivity and make navigation more intuitive.
The Modern Web Client offers a sleek, NEW Outlook-like design that some users adore.
However, don’t worry the familiar Classic Web App. will still be available for you after the migration.
You can explore the Modern Web App and decide if you like it.

Important Notes:

Minimizing email re-sync after migration

When a user’s mailbox is moved to a Zimbra 10 server, sync tokens are reset, causing mobile or IMAP clients to resync the entire mailbox. Users may notice their email disappearing from their phone or IMAP client temporarily until it reappears after the resync completes. This may happen a few times, especially for users with large mailboxes or many folders.

As a result of this, if you have set a long sync period on your device, we strongly recommend that you now set this as short as possible (e.g., two weeks), ahead of the upgrade. Once your mailbox is migrated to Zimbra 10, you may then extend the sync period to what it was previously. This will speed up the resync process.

Note: Apple mail clients have short timeouts and request the entire mailbox folder tree to refresh before syncing any emails. If you are on a slow Internet connection, the mailbox may appear to populate and then disappear, indicating the folder refresh did not complete in the time Apple allows. For this reason, it is best for the mobile device to be on a fast wireless connection to minimise disruption.

Keep in mind that if you are facing any inconveniences, you may elect to use the Zimbra iPhone/iPad App, or the webmail interface.