Turbine 9.5 - Release notes

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

VSF-Turbine (vsft) is a firmware for Zenitel devices based on the IMX28 processor.

Release info

Name: VSF-Turbine
Description: VSF-Turbine is a firmware for Zenitel devices based on the IMX28 processor.

The firmware is delivered in two different ZIP archives and one swu file:

• vsft-9.5.x.x - Used for standard in-field upgrades
• vsft-prod-9.5.x.x - Used in production- and recovery upgrades

Version: vsft-9.5.3.0
Date: 10.06.2026
Status: General Availability

VSF-TURBINE 9.5.3.0

New features

MTN-4885 New TFIX‑V2 option: Route audio to external loudspeaker only during “Volume Override”

A new configuration option in TFIX‑V2 makes it possible to use the internal loudspeaker for normal calls while directing audio to the external loudspeaker only during volume override/alarm calls.

To enable this behavior, select “Only Volume Override” for the External Loudspeaker in the Audio Settings within the TFIX web interface.

Fixed Issues

MTN-4917 Updated loudspeaker Dynamic Range Compression (DRC) implementation

The DRC (Dynamic Range Compression) algorithm has been transitioned from hardware‑based to software‑based processing within the AEC (Acoustic Echo Cancellation) signal path. This improves open‑duplex performance and reduces the risk of acoustic echo and return‑path issues.

Software‑based DRC also enables better handling of varying far‑end signal levels, improving overall audio consistency on devices with power‑limited loudspeaker amplifiers.

Note: This update changes the DRC behavior and the effective gain compared to the previous hardware‑based implementation, and may affect perceived output volume.

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-1742 TFIX‑V2 internal loudspeaker SPL improvement – updated EQ and amplifier tuning

The TFIX‑V2 internal loudspeaker has limited output power due to the ATEX approval requirements.

To enhance audio performance, the EQ filter profile has been optimized and the speaker amplifier gain has been fine-tuned. For best voice clarity and SPL performance, it is also recommended to use the updated DRC (dynamic range compression) algorithm in TFIX-V2.

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-1682 and DS-1683 Security Update

Resolved vulnerabilities related to:

• CVE-2025-15467 - Stack buffer overflow
• CVE-2023-48795

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

Known issues

MTN-4883 The default microphone signal from the IP Hotline station (1008070010) is too high

Audio from the IP Hotline handset is louder than audio from other devices. Workaround is to adjust the Microphone gain to -10dB in the Audio Settings in the web interface of the IP Hotline station.