Exchange Server 2016 and 2019 ESU Ends in October 2026: What Businesses Need to Know

Microsoft Exchange Server 2016 and Exchange Server 2019 have already reached the end of their official support period. For organizations that are still running these versions, Microsoft's Extended Security Update (ESU) program provides temporary security coverage — but that coverage ends in October 2026.

This gives businesses a limited window to plan their next step.

For companies in Saudi Arabia that still depend on Exchange Server 2016 or 2019 for business email, calendars, contacts, and other communication services, now is the time to review their current environment and migration plans.

What is happening to Exchange Server 2016 and 2019?

Microsoft ended support for both Exchange Server 2016 and Exchange Server 2019 on October 14, 2025.

After that date, Microsoft introduced an Extended Security Update program for eligible organizations that needed additional time to move away from these older versions.

The current ESU period ends on October 31, 2026.

This means businesses that are still using Exchange Server 2016 or 2019 should not treat the ESU deadline as a new support date. It is a temporary security update period that gives organizations more time to move to a supported Exchange solution.

What does the October 2026 deadline mean?

Once the ESU period ends, organizations running Exchange Server 2016 or 2019 will no longer have the same security update coverage available through the ESU program.

For businesses, continuing to rely on an unsupported Exchange version can create several concerns:

• Increased security risks
• Greater difficulty maintaining the environment
• Limited access to Microsoft support
• More challenges when addressing future security requirements
• A growing gap between the existing Exchange environment and Microsoft's supported versions

The exact impact will depend on each organization's setup, applications, security requirements, and business needs.

What should businesses using Exchange 2016 or 2019 do?

There is no single migration path that is right for every organization.

The first step should be to review the current Exchange environment and determine which option fits the business.

1. Move to Exchange Server Subscription Edition

Microsoft's current direction for organizations that need to continue running Exchange Server on their own infrastructure is Exchange Server Subscription Edition (SE).

Exchange Server SE is the supported Exchange Server option that replaces the older 2016 and 2019 versions.

Moving to Exchange Server SE can provide a path for organizations that need to continue managing their email environment on their own infrastructure while moving away from unsupported Exchange versions.

2. Consider Microsoft 365

For some organizations, moving email services to Microsoft 365 may be a better fit.

Microsoft 365 can reduce the need to maintain Exchange servers on-site and provides access to Microsoft's cloud-based email and collaboration services.

However, the right choice depends on factors such as the company's existing systems, security requirements, data needs, user numbers, and business plans.

3. Review the existing environment before making a decision

Before starting a migration, businesses should understand what they currently have.

A proper review should consider:

• Exchange Server versions and updates
• Number of users and mailboxes
• Mailbox sizes
• Applications connected to Exchange
• Email security and backup
• Existing Microsoft 365 services
• User and access requirements
• Business applications that depend on email
• Migration requirements and possible downtime

This review helps businesses avoid unexpected problems during the move.

Why should businesses start planning now?

October 2026 may seem like enough time, but an Exchange migration is not simply a matter of installing a new version.

Businesses need time to review their environment, choose the right destination, prepare users, test the migration, and move mailboxes and connected services.

Starting early also gives IT teams more time to identify older applications or configurations that may need attention before the migration.

For organizations with large or complex Exchange environments, early planning can make the transition easier to manage.

Exchange migration in Saudi Arabia

For Saudi businesses, an Exchange migration should also be considered as part of the organization's wider IT and security plans.

Email is often connected to other business systems, user accounts, applications, security controls, backup systems, and daily operations. Moving Exchange without reviewing these dependencies can create unnecessary disruption.

A structured migration plan can help businesses:

1. Assess the current Exchange environment
2. Identify dependencies and risks
3. Select the appropriate Microsoft solution
4. Prepare the target environment
5. Test the migration
6. Move users and mailboxes in stages
7. Check email flow and connected applications
8. Complete the transition and review the environment

What about businesses that are already planning to migrate?

If your organization already has an Exchange migration project underway, the October 2026 ESU deadline is an important date to include in your planning.

It is also worth checking whether the current migration plan is based on Exchange Server SE, Microsoft 365, or another supported Microsoft solution.

The goal should not simply be to move away from Exchange 2016 or 2019. The new environment should also support the organization's security, business, user, and future IT requirements.

How Ctelecoms can help

As a Microsoft Gold Partner in Saudi Arabia, Ctelecoms helps businesses assess, plan, and implement Microsoft solutions based on their existing IT environment and business requirements.

Our team can help organizations running Exchange Server 2016 or 2019 review their current environment and plan their move to a supported Microsoft solution.

This can include:

• Exchange environment assessment
• Migration planning
• Exchange Server Subscription Edition planning
• Microsoft 365 migration planning
• Security and backup review
• Migration preparation and testing
• Mailbox and user migration
• Post-migration support

If your business is still running Exchange Server 2016 or 2019, October 2026 is an important deadline to plan for now.

Talk to Ctelecoms' Microsoft experts to review your Exchange environment and plan your next step.