VSF-Fortitude6 9.5 Release Notes

• Previous Release - VSF-Fortitude6 9.4 Release Notes

This document provides the release notes for VSF-Fortitude6 9.5 with incremental bug fix releases. The release notes describe new features, improvements and issues fixed after VSF-Fortitude6 9.4.3.1.

Release info

Name: VSF-Fortitude6
Description: VSF-Fortitude6 is a firmware for Zenitel devices based on the IMX6 processor.

The firmware is delivered in two different files:

• vsff6-9.5.3.x - Used for standard in-field upgrades
• vsff6-prod-9.5.3.x - Used in production- and recovery upgrades.

Version: 9.5.3.0
Date: 10.06.2026
Status: General Availability

VSF-FORTITUDE6 9.5.3.0

Improvements

DS-1744 CRM-V-2 Improved audio frequency response on Mic and Loudspeaker signals

Audio tuning updates have been introduced on the CRM-V2 to improve speech intelligibility, reduce distortion, and enhance audio switching performance. These improvements deliver a clearer, more natural voice experience in both half-duplex and open-duplex communication.

To maximize output levels where higher SPL is desired, the DRC (Dynamic Range Compression) feature can be enabled to boost perceived loudness while maintaining the improved audio clarity.

DS-1743 IPDM-V2 Improved audio frequency response on Mic and Loudspeaker signals

Audio tuning updates have been introduced on the IPDM-V2 to improve speech intelligibility, reduce distortion, and enhance audio switching performance. These improvements deliver a clearer, more natural voice experience in both half-duplex and open-duplex communication.

As a result of the optimized frequency response, maximum measured sound pressure levels may be slightly lower in some configurations compared to previous software versions.

To maximize output levels where higher SPL is desired, the DRC (Dynamic Range Compression) feature can be enabled to boost perceived loudness while maintaining the improved audio clarity.

Fixed Issues

MTN-4860 Fixed an issue where calls using SRTP encryption could produce random noise at the start

In delayed-offer SIP scenarios (e.g., with IPC Unigy), encrypted audio packets could arrive before the decryption key was established. The device now silently discards these packets, ensuring clean audio from the start of every encrypted call.

DS-1728 Fixed voice quality issue during duplex communication on IPDM-V2 and CRM-V2

Resolved an issue where voice quality could degrade during duplex (two-way) communication on IPDM-V2 and CRM-V2 stations, particularly at higher volume levels.

Optimized audio filters for loudspeaker and microphone now significantly reduce distortion, delivering clearer and more intelligible voice communication. As part of this fix, the default maximum voice volume has been adjusted to ensure distortion-free audio. To achieve the same or higher perceived loudness with improved clarity, enable the DRC (Dynamic Range Compression) option in the station configuration.

Security fixes

DS-1720 Disabled SNMP port by default in firewall

The SNMP port is now disabled by default in the firewall on all new and factory-reset devices. Customers who require SNMP must enable it manually in the device configuration before use.

DS-1683 Security Update

Resolved vulnerabilities related to CVE-2025-15467 - Stack buffer overflow

Action: Upgrade to 9.5.3.0 or later

DS-1662 The SSH password to Zenitel devices in 9.5 release has been changed

Due to stricter cybersecurity requirements Zenitel has decided to protect against threats by limiting SSH access