How CDW Can Make Your Microsoft Exchange Server Upgrade Smooth, Sure and Safe

What's Inside

Preparing your Microsoft Exchange Server for the upgrade
Once the first cumulative update of Microsoft Exchange Server SE (arriving in October 2025) is installed, all preceding versions will stop functioning.
What’s changing in Microsoft Exchange Server SE and Exchange Online?
Microsoft Exchange Server SE and Exchange Online will bring about the following changes.
Two ways to make the upgrade
Once you have brought your current Exchange Server version up to 2016 CU23 or newer, there are two ways to upgrade to Server Exchange SE.
Upgrade challenges and hurdles you should be aware of
The upgrade process is heavily influenced by the infrastructure and policies in place, which is why it may look different for each organization. Here are a few noteworthy challenges you might need to prepare for.
Upgrade your Microsoft Exchange Server confidently with CDW
CDW Canada, the 2023 Microsoft Modern Workplace Partner of the Year, is committed to delivering a smooth, sure and safe upgrade for Canadian organizations.

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Microsoft is rolling out the latest version of their Exchange Server, the widely used email and business collaboration platform, with enhanced features and security. As a part of this upgrade, all current versions of Exchange Server (2016 and 2019) will go out of support on October 14, 2025.

Once the support ends, Microsoft will no longer provide security updates, bug fixes or technical support for the older versions of Exchange Server, which can impact existing customers should vulnerabilities arise.

Moving to the newest version – Microsoft Exchange Server Subscription Edition (SE) or Exchange Online – will require careful migration planning to avoid obstacles. With less than a year of official support remaining, organizations should start planning now.

In this blog, we unpack the must-know details of this major upgrade and show you how CDW can help customers make a smooth transition with our dedicated end of support migration services.

Preparing your Microsoft Exchange Server for the upgrade

In earlier editions of Exchange Server, you could run two different versions (even unsupported ones) together within the same organization. This won’t be the case with Microsoft Exchange Server SE, as its setup will block coexistence with the previous versions.

Once the first cumulative update of Microsoft Exchange Server SE (arriving in October 2025) is installed, all preceding versions will stop functioning.

Your current Exchange Server version matters

Your current Exchange Server infrastructure could be running on-premises, in the cloud or in a hybrid state and may have versions older than the 2013 release.

In such cases, you must first upgrade to a minimum Exchange Server 2016 CU23. This will bring you on track for migrating to Microsoft Exchange Server SE.

If you’re using Exchange Server 2019, Microsoft recommends updating to CU14 to be ready for the upgrade.

Server administrators can determine their current Exchange Server version by using the Microsoft Exchange Management Shell. If the version number starts with 15.0 or less, you’re using the 2013 or older release, which will require you to upgrade to the 2016 release at least.

Exchange Server Version	Key Dates	Preparatory Actions to Take	Next Steps
Exchange Server 2013	End of support on April 11, 2023.	Migrate to Exchange Server 2016 CU23 or 2019 CU14.	Migrate to Exchange Online or Exchange Server SE and decommission old versions.
Exchange Server 2016	End of support on October 14, 2025.	Clients need to either switch to Exchange Online (EXO) by the deadline or set up a new Exchange 2019 system alongside Exchange 2016, migrate to Exchange Online and then upgrade to Exchange 2019 and beyond.
Exchange Server 2019	End of support on October 14, 2025.	Prepare for upgrading to Exchange Online or Exchange Server SE CU1.

What’s changing in Microsoft Exchange Server SE and Exchange Online?

Microsoft Exchange Server SE and Exchange Online will bring about the following changes:

Introduction of Kerberos for server communication

Kerberos is a protocol used for secure network authentication, which will replace the NTLMv2 protocol in the latest Exchange server.

This will introduce a stronger security model and scalability for authenticating users across files, messages and shared resources. It’s already widely used in Microsoft Active Directory.

Introduction of the Admin API

The Admin API will replace Remote PowerShell (RPS) protocol for remote management functions. This is a modern way for communicating with the Exchange Server. Rather than logging in remotely, administrators would be able to use the Admin API for executing managerial changes.

Licencing model changes

Starting with Exchange Server SE, the software will require subscription licences for servers and users, as seen in SharePoint Server Subscription Edition.

However, free hybrid server licences will still be available for hybrid installations using the Hybrid Configuration Wizard.

Two ways to make the upgrade

Once you have brought your current Exchange Server version up to 2016 CU23 or newer, there are two ways to upgrade to Server Exchange SE.

1. Make a legacy upgrade

A legacy upgrade refers to introducing a newer version and moving the mailboxes from the older version to the new version. Once this is achieved, the old version can be removed from the environment.

This method can be used for upgrading from Exchange Server 2016 to Exchange Server 2019 and Exchange Server SE, as well.

2. In-place upgrade to Exchange Server SE

This option is usable only if you’re currently on Exchange Server 2019. It allows for a direct upgrade to Exchange Server SE from Exchange Server 2019 CU14/CU15.

The process is similar to installing the cumulative updates and can be managed from within the application.

Beyond the upgrade methods, server administrators have a number of considerations such as the infrastructure requirements, data integrity and change management.

Upgrade challenges and hurdles you should be aware of

The upgrade process is heavily influenced by the infrastructure and policies in place, which is why it may look different for each organization. When you plan to migrate to a new version, it’s worth reviewing the roadblocks and risks well in advance.

Here are a few noteworthy challenges you might need to prepare for.

Compatibility issues: Compatibility with existing applications, third-party add-ons and custom scripts may be affected by the upgrade.
Data migration risks: Moving mailboxes and other data can be complex, with risks of data loss or corruption.
Downtime: Ensuring minimal downtime during the transition is challenging, especially in organizations with high email usage.
User disruption: Upgrades may lead to client-side configuration changes, causing disruptions for end users.
DNS and network configuration: Updates to network and DNS settings may cause delays or connectivity issues.
Compliance: Ensuring the new configuration complies with organizational policies and regulatory standards can be a challenge.

In addition to the above list, there could be several specific challenges that may arise during the upgrade. We recommend creating a systematic upgrade plan to tackle challenges ahead of time.

Upgrade your Microsoft Exchange Server confidently with CDW

Exchange Server is the backbone of business email and collaboration for Microsoft customers, making the upcoming upgrade an inevitable one from security and continuity standpoints.

CDW Canada, the 2023 Microsoft Modern Workplace Partner of the Year, is committed to delivering a smooth, sure and safe upgrade for Canadian organizations.

CDW has a pool of 40+ dedicated Microsoft and 100+ security professionals who are trained to gold standard level, ready to assist you with the entire migration process.

Our expertise in Microsoft products ensures that your migration complies with the best practices and future updates.

Our Exchange Server upgrade process

Assess: Evaluate all Exchange servers in your organization, noting their roles and dependencies. Perform comprehensive security audits to find and fix vulnerabilities before support ends.

Architect: Evaluate the roadmap of transitioning to Exchange Online or upgrading to the forthcoming Exchange Server Subscription Edition (Exchange Server SE), set for release in Q3 2025. Additionally, review and enhance access controls to ensure that only authorized individuals can access sensitive information.

Implement: Collaborate with you to create a migration strategy aimed at minimizing disruptions to your business operations. Ensure that all patches and updates are applied to your Exchange Servers before support ends to reduce security risks.

Additionally, develop an incident response plan to swiftly tackle any security breaches or issues that may occur during or post-migration.

Resources available to our customers

Dedicated portal to manage your own licence (csp.cdw.ca)
A team of highly certified Microsoft solution architects with 30+ Microsoft certifications
A dedicated Microsoft solutions specialist who is your first point of contact for all things Microsoft

Start your Exchange Server migration journey with CDW and optimize the time, costs and resources needed for the upgrade. Talk to our Microsoft experts to discuss your current version, infrastructure and migration plan options.