Outlook 365 / 2021 / 2019 / 2016 Update for May 2023

The May security and rollup update has been made available for all Click-to-Run installations of Outlook 2016, Outlook 2019, Outlook 2021 and Outlook as part of a Microsoft 365 subscription.

It contains 4 security updates for Access (1), Excel (1), Word (1), and Office (1).

In addition, it contains 2 documented non-security fixes related to Outlook Current Version 2304, 5 new features and 12 fixes for Monthly Enterprise Version 2303, 2 fixes for Monthly Enterprise Version 2302, and 2 fixes for Semi-Annual (Preview) Version 2302. Most notable fixes are;

  • Version 2304
    • We fixed an issue that caused users of the Event-Based feature to be unable to utilize some of the new APIs included in Mailbox Requirement Set 1.13.
    • We fixed an issue where drafting a new email and @mentioning an Outlook contact group (a contact group that is created locally) in the email body wouldn’t add the contact group to the ‘To’ field.
  • Version 2303
    • Get relevant alerts with new Notifications pane
      Don’t let important information get buried in your inbox. The new Notifications pane in Outlook delivers notifications that are relevant to you in the context of your regular email. The pane gives you the ability to customize the types of notifications you wish to receive, including email and document @mentions, travel updates, deliveries, and more.
    • Prevent data leaks more easily with the new Sensitivity toolbar
      Sensitivity labels powered by Microsoft Purview Information Protection are now displayed next to the message Subject line, allowing you to easily recognize and adhere to your organization’s policies.
    • Disable the Azure Information Protection Add-in by default
      Office apps will now automatically disable the legacy Azure Information Protection add-in and use the built-in sensitivity labels to view and apply labels powered by Microsoft Purview Information Protection.
    • We added a registry key that hides the “Try the new Outlook” toggle
      • Key: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General
      • Value type: REG_DWORD
      • Value name: HideNewOutlookToggle
      • Value: 0 (default) – “Try the new Outlook” toggle, if available in selected update channel, is displayed to users.
      • Value: 1 – “Try the new Outlook” toggle is hidden.
    • Inheritance of attachment labels to email messages
      For email messages with attachments, apply a label that matches the highest classification of those attachments.
    • We fixed an issue that caused the Sub-folders search scope to be broken when searching in the Online Archive.
    • We fixed an issue where some users may be unable to view or access group email messages and calendars in the Outlook desktop client.
    • We fixed an issue that caused Outlook to close unexpectedly when using Loop Components in an email.
    • We fixed an issue that caused users with an Outlook.com account in their profile to be prompted for their password and to receive the following error message: “You cannot log in with a personal account. Use your work or school account.”
  • Version 2302
    • We fixed an issue where the “From” field and Signatures were not working while using Google Workspace Sync for Microsoft Outlook.
    • We fixed an issue that caused users to see the message body flash white when closing a message.

Based on your release channel, you’ll be updated to the following version;

  • Microsoft 365 Apps, Outlook 2016 Retail, Outlook 2019 Retail, Outlook 2021 Retail
    Version 2304 (Build 16327.20248)
  • Monthly Enterprise
    Version 2303 (Build 16227.20318)
    Version 2302 (Build 16130.20500)
  • Semi-Annual Enterprise (Preview)
    Version 2302 (Build 16130.20500)
  • Semi-Annual Enterprise
    Version 2208 (Build 15601.20660)
    Version 2202 (Build 14931.21000) 
  • Outlook LTSC 2021
    Version 2108 (Build 14332.20503)
  • Outlook 2019 Volume Licensed
    Version 1808 (Build 10398.20008)

Note: Depending on your installation type, this update can be installed via the Update Now button in Outlook itself or the Microsoft Store. This update does not apply to msi-based installations of Office 2016.