SmartSDR v4.2.18 Update: DAX v2, ARM Support and New SmartSDR+ Features

Updated 2026-05-01

FlexRadio has released SmartSDR v4.2.18, a significant upcoming update for SmartSDR+ and compatible FLEX radios. SmartSDR v4.2.18 introduces a major rework of DAX, updated Windows driver support, new SmartSDR+ operating features, and a long list of fixes and improvements.

Watch the video below for an overview of what is new, then continue down the page for the detailed update summary.

Early User Feedback

Early comments from FlexRadio users have been encouraging, especially around the smooth upgrade process, the redesigned DAX system, and improved Windows 11 compatibility.

Smooth installation: Several early users reported that the SmartSDR v4.2.18 upgrade installed cleanly and without major issues on FLEX-6000 series radios.
DAXv2 praised for FT8: One early user reported that the redesigned DAXv2 system resolved previous FT8 transmit audio stuttering and allowed Windows 11 Memory Integrity / Core Isolation to remain enabled.
Older radios still supported: A FLEX-6300 owner noted that the new version was installed and running well on his more than 12-year-old radio.
Positive beta experience: Long-time FlexRadio user K9ZW reported making hundreds of contacts during beta testing across SSB, AM, FT8, and CW, describing SmartSDR v4.2 as a release that “simply rocks.”

SmartSDR v4.2.18 Detailed Updates

Major Changes

DAXv2: DAX has been completely re-architected with a new audio-transfer architecture, lower latency, and improved Windows compatibility and stability.
Native x64 and ARM support: SmartSDR for Windows, CAT, DAX, and FlexVSP drivers now support modern 64-bit and ARM Windows systems.
Updated FlexVSP driver: Improved support for x64 and ARM Windows 11 systems.
MSI-based installer: The installer now includes improved dependency handling and repair/self-healing behavior.

New SmartSDR+ Early Access Features

Band Plan / Band Edge Markers: IARU Region 1, 2, and 3 selectable band-plan overlays on the panadapter.
User-configurable RX filters: Receive filters can now be configured per mode.
TX filter display: The transmit filter is displayed on the panadapter, which is especially useful when operating close to band edges.

New Basic Features Available to All Users

Updated US 60 m allocation without requiring a new US TURF file.
ARM processor support for SmartSDR, CAT, DAX, and FlexVSP.
External sampler support for SmartSignal/APD when using external amplifiers.
APD reset button.
Waveform deployments using FlexRadio’s open API and Docker container for Aurora and FLEX-8000 radios.

Notable Fixes

Multiple DAX driver fixes, including installation, Windows security, Realtek driver conflict, and ghost audio port issues.
FlexVSP driver improvements after Windows 11 updates.
Added and modified TURF regions, including Czech Republic, South Africa, Portugal, India, Ireland, and Italy 160 m.
Fixed ANF behavior for FLEX-6000 radios.
Fixed CAT startup behavior on fast PCs.
Several APD and SmartSignal fixes.

Upgrade Notes

Before upgrading, FlexRadio recommends exporting your Global, TX, and Microphone Profiles. It is also recommended to update Windows first, power-cycle the radio before installation, and perform a cold boot after the firmware upgrade. Downgrading is not recommended. If a downgrade is required, FlexRadio advises performing a factory reset because the radio database is not backward-compatible.

Compatibility Notes

32-bit Windows is no longer supported in SmartSDR v4.2.
Windows 10 is no longer supported for FlexRadio software support.

Read the official SmartSDR v4.2.18 release notes from FlexRadio. Explore FlexRadio products and accessories in the PileupDX.com FlexRadio department.