Important Announcements

Cisco Secure Email Add-Ins No Longer Supported on Microsoft Outlook 2019

This is to inform you that, effective October 14, 2025, Microsoft Outlook 2019 is no longer supported for the Secure Email Encryption Service Add-In and Secure Email Submission Add-In.

To continue using these Add-Ins, we recommend upgrading to Microsoft 365. Starting October 2025, download and install the new manifest for:

- Secure Email Encryption Service Add-In from the CRES Admin Dashboard

- Secure Email Submission Add-In from the Cisco Software Download Portal

After downloading the manifests, follow the instructions provided in the Submission and Encryption Add-In guides. For more information, see: Cisco Email Encryption - End-User Guides.

TLS 1.0/1.1 Deprecation from AsyncOS for Secure Email Gateway, Starting version 16.5

We would like to inform you that starting with the AsyncOS 16.5 release, TLS versions 1.0 and 1.1 will no longer be available as configuration options in both the CLI and GUI.

To ensure secure email delivery and receipt, you should use TLS versions 1.2 and 1.3. These versions can be configured via the sslconfig CLI command or through the System Administration > SSL Configuration menu in the user interface.

For detailed instructions on updating TLS versions, please refer to the “System Administration” section of the User Guide for AsyncOS 16.0.x for Cisco Secure Email Gateway.

How to address EMAIL SPOOFING on ESA