Firmware Updates Zyxel V5.40 for ATP and USG FLEX Series

In May 2025, Zyxel released firmware version V5.40 for the ATP and USG FLEX product lines. These updates focus on improving system performance, security, and usability. The table below summarises key enhancements for each model.

🔔 Note: The following table offers a general overview. For complete details, please refer to the corresponding Release Notes linked in the last column.

The firmware files themselves can be downloaded from the Zyxel Download Library on each product’s page. Visit the Zyxel Download Center, select your device model, and navigate to the firmware section to access the latest updates.

Zyxel Firmware V5.40 – Key Updates and Enhancements

The latest firmware update for Zyxel's ATP and USG FLEX series, version 5.40, introduces critical enhancements and new features designed to improve security, user experience, and functionality.

Security Best Practices

New guided, step-by-step setup process consolidates security reminders. Integrated single-flow reminders for configuration completeness. Specific prompts include Two-Factor Authentication (2FA), regular admin password updates, policy control activation, web interface security checks, and license expiration warnings.

Two-Factor Authentication (2FA)

• Mandatory for admin-type accounts.
• Setup via Google Authenticator directly through the guided interface.

Password Change Requirement

• Password change prompted for admin accounts unchanged over 60 days.
• Immediate application and verification via interface.

Security Policy Control

• Detection and activation prompts for policy control if inactive.
• Quick activation through guided prompts.

Web Interface Security Checks

• Prompts users to restrict access by IP addresses or geolocation.
• Immediate implementation of restrictions via guided setup.

Security License Warnings

• Notifications appear if security licenses expire, directing users to marketplace for renewal.
• Option to bypass specific reminders marked as "Skipped" with subsequent greyed-out notifications.

Abnormal TCP Traffic Log

• Improved logging system identifies abnormal TCP/UDP traffic, specifically ports set to zero, indicating possible security threats.
• By default, logs categorized as Debug to prevent user overload.
• Enhanced debugging features available for troubleshooting.

Removing Diffie-Hellman Ephemeral (DHE) Key Exchange

• Removed from SSL VPN, SSH, FTPS, and HTTPS services due to inefficiency and vulnerability concerns.
• Commands available for SSH, FTPS, and HTTPS to re-add DHE if necessary, while SSL VPN supports modern secure key exchanges only.

WiFi 7 AP Integration

• Supports new WiFi 7 access points (WBE530, WBE510D, WBE630S).

ZLD Mesh Capability

• ZyMesh not supported in WiFi 7 APs; notifications and reminders incorporated for clarity.
• Mesh functionality in WiFi 7 series available exclusively with the new USG FLEX H series firewalls.

APC Operation Mode for WiFi 7 AP

• Removed Root AP and Repeater AP options from WiFi 7 APs to streamline operations.
• Alerts on limited mesh functionality displayed for user clarity.

Wireless Health Enhancement

• Station monitoring interval reduced from 3 minutes to 1 minute to proactively manage poor signal quality by reassigning stations to nearer APs.

These comprehensive updates aim to strengthen network security, improve user interaction, and ensure robust performance across Zyxel's firewall and AP management solutions.

Firmware Enhancements Table

Release Notes Links

You can access all release notes from the Zyxel Download Library or directly from the links above.

Let me know if you'd like this exported as a Word, HTML or Markdown file for publishing.