While the next version of Exchange Server is not expected until 2025, the upgrade path to that version will be smoother if administrators plan to migrate to Exchange 2019 soon.
Despite the popularity of Exchange Online, many organizations opt to retain Exchange Server on-premises, some using a hybrid mode where some services run locally and others in Microsoft's hosted email environment. However, as the upcoming version of Exchange vNext gets closer, Microsoft is recommending organizations plan to migrate to Exchange 2019 soon and move from older versions of Exchange. This guidance for Exchange Server customers is meant to ease the transition to Exchange vNext, expected sometime in the second half of 2025, because in-place upgrade will not be available for other Exchange versions.
Why some organizations stay with on-premises Exchange Server
There are many reasons why some customers may still be interested in this upcoming upgrade rather than move to Exchange Online.
For some, on-premises Exchange Server satisfies data storage requirements where information must be retained within the firewalls of the organization. On other cases, there may be an integration constraint that mandates the use of Exchange Server to communicate with the messaging platform.
What features does Exchange Server 2019 have?
Organizations that migrate to Exchange 2019 will benefit from functionality not available in previous versions of Exchange Server. Microsoft offers support to run this as a Server Core workload, which eliminates several components in the full Windows Server version and is theoretically more secure due to its smaller attack surface.
Exchange Server 2019 also provides support for enhanced security features, such as blocking external access to the Exchange admin center and Exchange Management Shell. Another security benefit is Exchange 2019 uses Transport Layer Security (TLS) 1.2 by default.
Additional Exchange 2019 features include enhanced performance on the search component to index bigger files. It also supports servers with up to 256 GB of RAM and up to 48 CPU cores.
On the client side, Exchange Server 2019 adds calendar forward blocking, away/out-of-office support, better support for the removal of calendar invites through PowerShell and email address internationalization (EAI) when emails contain non-English characters.
Exchange 2019 server also introduced a new look for Outlook on the web (OWA). The new interface delivers better interactions on a mobile device regardless of whether the platform is Android or iOS. In addition to a more mobile-friendly look, Microsoft added features such as contact linking between users and their LinkedIn accounts, new look and feel for the calendar, performance improvements, new Outlook on the web action pane, link preview, additional themes, and search suggestions and refiners on the UI.
What are the requirements for Exchange Server 2019?
To get Exchange 2019 server deployed, administrators will need to ensure they use Windows 2016 in either the Standard or Datacenter editions with an Active Directory forest functional level at Windows Server 2012 R2 or higher.
Exchange 2019 requires a 64-bit based processor that uses either of the following:
- An Intel processor that supports Intel 64 architecture (formerly known as Intel EM64T).
- An AMD processor that supports the AMD64 platform.
As for memory, these are the following requirements:
- Mailbox: 128 GB minimum recommended.
- Edge Transport: 64 GB minimum recommended.
These are the requirements for disk space:
- At least 30 GB of free space on the installation drive.
- At least 200 MB of free space on the system drive.
- At least 500 MB of free space on the drive that contains the message queue database.
Administrators must also prepare the client machines to meet the Exchange Server 2019 Outlook requirements. The versions supported by the Exchange 2019 include the following:
- Microsoft 365 Apps for enterprise.
- Outlook 2021.
- Outlook 2019.
- Outlook 2016.
- Outlook 2013.
- Outlook for Mac for Office 365.
- Outlook 2016 for Mac.
On the licensing side, organizations will need Software Assurance and Client Access Licenses.
How do you test the upgrade to Exchange 2019?
The migration process to the latest Exchange server is not complete until administrators test the upgrade. To ways to do this include cloning the server and performing an upgrade to confirm the functionality or performing a fresh backup of the production server then executing the upgrade to see how it performs with the option to revert if it fails.