These release notes for ExtremeCloud Tunnel Concentrator version 25.05.01.0018, issued in April 2026, outline new features, resolved issues, known issues, and documentation resources. This release introduces enhanced redundancy and failover enhancements for deployments that are managed by ExtremeCloud IQ with the ability to assign primary, secondary, and tertiary tunnels to a Tunnel Concentrator-enabled user profile. In addition, you can now obtain the serial number for a freshly installed instance from Universal Compute Platform. For ExtremeCloud IQ-managed deployments, this update lets you handle onboarding and licensing from ExtremeCloud IQ without having to use the Tunnel Concentrator GUI. This document provides links to installation, configuration, and maintenance guides, and offers multiple channels for obtaining technical support and subscribing to product announcements. Revision AB features minor corrections to Known Issues.