Microsoft is officially retiring Outlook on the Web (OWA) Light. First introduced nearly 20 years ago to support legacy browsers and slow network connections, the lightweight email interface has reached the end of its journey.

In an upcoming Exchange Server SE update, estimated for August 2026, Microsoft will permanently disable and remove OWA Light. Exchange Server 2016 and 2019 won’t receive this update automatically, since both already reached end of support in October 2025, but Microsoft’s original 2024 deprecation notice still applies to them, and organizations on those versions should treat this as another reminder to move on.

What Admins Need to Know

Once the update is applied, users will no longer see the option to load the simplified interface. Instead, everyone will be automatically routed to the standard, modern Outlook on the web experience.

Cutting OWA Light seems like an easy call — until you hit the one customer scenario that would’ve broken just months ago. This customer ran a large legacy point-of-sale deployment, the kind of environment that lives on Windows Embedded and relies on older browsers (and OWA Light) for compatibility. Fortunately, they finished migrating off that legacy system just in time.

Because modern web browsers are now highly optimized and standard internet speeds have vastly improved, the legacy platform is no longer necessary. Removing it allows Microsoft to streamline its engineering and reduce the overall attack surface of Exchange Server.

How Administrators Can Prepare

Admins should use the time now to identify any users, kiosks, helpdesk scripts, training material, or accessibility workflows that still depend on OWA Light, since those will need to move to the standard experience before the update arrives.

You do not have to wait until August to prepare your users. Microsoft recommends that Exchange administrators proactively disable OWA Light ahead of time to ensure a smooth transition to the full web client.

You can disable the feature immediately by running the following commands in the Exchange Management Shell:

# Disable OWA Light at the mailbox policy level
Set-OwaMailboxPolicy -OwaLightEnabled $false

# Confirm the policy is assigned to all mailboxes
Set-CasMailbox -OwaMailboxPolicy <PolicyName>

# Remove the OWA Light selection checkbox from the forms-based logon page
Set-OwaVirtualDirectory -LogonPageLightSelectionEnabled $false

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