Message Defence Is Reaching End of Life - Here’s What You Need to Know

After 15 years of protecting our customers from spam and unwanted emails, our Message Defence anti-spam solution will be retired in March 2026.

We want to ensure that every customer has the best possible protection in place. As a result, we have made the decision to move away from Message Defence and are recommending Microsoft 365 Business Premium, a modern and secure platform that can keep pace with current and emerging risks.

⚠️ From March 2026, Message Defence will be permanently switched off. Once Message Defence is turned off, you will stop receiving emails unless you replace it.

Messages will continue to try to queue on the server where filtering takes place, but with no system in place to let them through, if you do nothing, those emails will disappear, leaving your inbox empty.

What Should I Consider Switching To?

Our recommendation is switching from Message Defence to Microsoft 365 Business Premium.

Business Premium includes Microsoft’s advanced anti-spam and anti-phishing technology built into Microsoft Defender for Office 365. This is a modern, constantly evolving security platform that does far more than simply block junk mail. It actively scans, isolates and removes dangerous messages before they ever reach your staff, even if those threats are detected after delivery.

Here is what you can expect once you make the switch:

Advanced Spam Filtering

Microsoft 365 Business Premium uses cloud-based filtering powered by AI and global threat intelligence. This means it learns and adapts in real time as new spam techniques emerge. You are not relying on static rules or outdated definitions. The system constantly updates itself based on millions of data points gathered across Microsoft’s global network. This keeps inboxes clean and reduces time spent sorting through irrelevant or harmful messages.

Phishing Detection and Prevention

Phishing is one of the most common and dangerous email-based threats. Business Premium’s phishing protection analyses sender behaviour, domain reputation and link patterns to identify malicious intent, even if the email looks genuine on the surface. This significantly reduces the risk of staff clicking harmful links or revealing sensitive information.

Zero-Hour Auto Purge

Even advanced systems can occasionally let a malicious message through, especially if it is a brand-new threat. Zero-hour auto purge removes those messages from every affected inbox as soon as they are identified. If a dangerous email is delivered at 9am and flagged at 9:15, your team will never see it again.

Seamless Integration with Microsoft Defender

Business Premium integrates with Microsoft Defender to create a multi-layered security environment that protects email, files, cloud storage and devices. If a malicious link is detected in an email, Defender can check whether it has been opened in a document or stored in OneDrive, stopping an attack before it spreads.

Switching to Microsoft 365 Business Premium is not just about replacing one product with another. It is about giving your business a smarter, stronger defence against the single biggest route cyber criminals use to gain access — email.

What else is included in Business premium?

While replacing Message Defence with Microsoft 365 Business Premium will give you far stronger email security, the benefits do not stop there. Business Premium is a full productivity and security suite that brings together everything your team needs to work securely and efficiently in one place.

In addition to Microsoft Defender for Office 365’s anti-spam and anti-phishing tools, you will also have access to:

• SharePoint and OneDrive for cloud storage and secure file sharing.

• Microsoft Defender for Endpoint to protect devices against viruses, ransomware and advanced threats.

• Advanced security policies, such as conditional access and multi-factor authentication management.

• The full suite of Office apps, including Word, Excel, PowerPoint and Outlook, all integrated with your security tools. Also including:

• Microsoft Teams for secure chat, video calls and collaboration.
  
  

This means you are not just improving your email protection, you are consolidating your IT tools into a single, integrated platform that is easier to manage, more secure and more cost-effective.

See below a comparison guide that shows exactly how Microsoft 365 Business Premium stacks up against Message Defence and why it is the preferred choice for modern businesses.

Feature Comparison
Message Defence vs. Microsoft 365 Business Premium

Switching from Message Defence to Microsoft 365 Business Premium is a straightforward process when planned correctly, but it is important to start early. The change involves migrating your email security to Microsoft’s platform, updating configurations and ensuring all users are protected without interruption.

Here is what you can expect:

Initial Review and Planning
We will start by reviewing your current setup to understand how Message Defence is integrated with your email system. This lets us map out the migration steps and identify any special requirements for your business.

Migration Setup
We will configure Microsoft 365 Business Premium’s security policies to match your needs and gradually phase out Message Defence. This ensures there is no point in time when your business is left without protection.

Testing and Go-Live
Before making the full switch, we will test the new system with a small group of users to make sure everything is working smoothly. Once confirmed, we will roll it out to your entire organisation.

Training and Support
We will provide guidance to your team so they know what to expect, how to recognise security notifications and where to go for help if they have questions.

Timeframe
We recommend starting your migration as soon as possible to avoid delays or risks as we approach the March 2026 cut-off. Leaving it too late could mean being unprotected if there are any issues during migration.

If you are ready to begin, get in touch and we will work with you to schedule your migration and ensure a smooth transition.

PLEASE NOTE: If your organisation is still using a Sophos SG Firewall, it’s important to know that support for this product will also end in March 2026.

By upgrading to Microsoft 365 Business Premium, you’ll benefit from Microsoft Defender as part of your package. This not only strengthens your overall protection but also removes the cost and complexity of running two separate security solutions.

Next Steps

Message Defence will be retired in March 2026 and after that date it will no longer provide any email protection. To avoid any gaps in your security, now is the time to begin planning your migration to Microsoft 365 Business Premium.

The sooner we start the process, the smoother your transition will be. Acting early means:

• You will avoid any risk of being left unprotected at the March 2026 cut-off.

• We can schedule your migration at a time that suits your business operations.

• You can start benefiting from the enhanced security and productivity features of Business Premium right away.

If you are ready to begin, or simply want to talk through your options, please reach out below.

We are here to make this process as straightforward as possible and to ensure your business remains secure against modern threats.