
TUSBAudio - Thesycon USB Audio 2.0 Class Driver for Windows

Revision History


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V6.0.0 (27 November, 2025)
-----------------------------------------------------

* New: support for Windows 11 (25H2)

* New: ASIO supports float format (Additional Addon)

* New: Mixer supports float format (Mixer Addon)

* New: Mixer gain support soft ramp (Mixer Addon)

* Chg: x86 support discontinued (on request only)

* Chg: fulfill new attestation signing requirements:
    https://techcommunity.microsoft.com/blog/hardware-dev-center/driver-isolation-ruleset-changes-for-whcp-and-attestation-submissions/4461580

* Chg: API version 5.15 (for SDK):
    TUSBAUDIO_NOTIFY_OWN_PROCESS flag added for RegisterDeviceNotification
    TUSBAUDIO_NOTIFY_CATEGORY_ASIO_DEVICE_CHANGE new notification event category
    NotifyEvent_VolumeChangedInterrupt, NotifyEvent_MuteChangedInterrupt new notification events
    NotifyEvent_AsioDeviceSelectionChanged, NotifyEvent_AsioDevicePreferredChanged new notification events
    TUsbAudioStreamFormat struct now has a sampleFormat

* Chg: Spy statistics improved

* Chg: updated TL-SetupFx 2.25

* Fix: USB disconnect handling in MIDI and AC notify pipes


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V5.74.0 (20 December, 2024)
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* Chg: changed plugin API (DspPreGetProperty function added)

* Chg: removed old Win7/8 workarounds


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V5.72.0 (12 November, 2024)
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* New: support for Windows 11 (24H2)

* Chg: Windows 10 (1803) or higher required

* Chg: MIDI handling improvements

* Chg: mixer plugin improvements


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V5.70.0 (27 August, 2024)
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* Chg: updated TL-SetupFx 2.24

* Chg: updated TL-Installer 2.19

* Chg: multiple older/other .msi installers can be uninstalled before driver installation
       e.g. a new driver package replaces multiple older driver packages

* Chg: added FeatureUnitIdIn and FeatureUnitIdOut registry parameter to overwrite used feature units

* Chg: added IgnoreFeatureUnitIn and IgnoreFeatureUnitOut registry parameter

* New: API version 5.13, flags added:
         TUSBAUDIO_DEVPROP_FLAG_AUDIO_STREAMING_SUPPORTED
         TUSBAUDIO_DEVPROP_FLAG_MIDI_STREAMING_SUPPORTED

* Chg: SDK reference documentation improved

* New: added TL-USBDFU 2.66 to replace DFU functionality in the audio driver in future


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V5.68.0 (February 5, 2024)
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* Fix: Fixed a vulnerability in MSI installer, see CVE-2024-25376.
       The MSI installer allows a local attacker to execute arbitrary
       code with SYSTEM privileges via the msiexec.exe repair mode.

* Fix: Deadlock during wake up


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V5.62.0 (September 26, 2023)
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* New: API version 5.12

* New: Installer improvements

* New: update Spy tool

* Fix: unit descriptor parsing in audio control interface

* Chg: updated projects to Visual Studio 2022

* Chg: documentation

* New: support for Windows 11 (23H2)


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V5.58.0 (March 28, 2023)
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* New: Installer improvements

* New: audio interface class code can be configured


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V5.57.0 (February 20, 2023)
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* New: API version 5.11:
             - some API functions added
             - up to 24 TUsbAudioStatsDevice and TUsbAudioStatsAsioHost in statistics struct supported

* New: fields on control panel info page can be hide via configuration

* Fix: USB buffer size was not correctly set after start and ASIO instance change

* Chg: TL-Installer 2.0

* Chg: version resources of the self-extractor for the .msi files are patched now

* Chg: ASIO instance selection in control panel is now only visible if more than one ASIO instance is configured

* Chg: clock source is now restored by default at driver start

* Chg: Spy icon updated

* Chg: switched to EWDK_W11_22000_210604


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V5.50.0 (September 8, 2022)
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* New: support for Windows 11 (22H2) x64

* New: support for Windows 11 (22H2) arm64

* Fix: USB IN buffer count was limited to 16 buffers, this lead to not enough buffers for high ASIO buffers sizes (e.g. 48kHz and 1024 samples)

* Fix: preferred ASIO buffer size are not restored after driver unload/load

* Fix: MIDI functions could become a ASIO device (e.g. if the device has dedicated Audio and MIDI functions)

* Chg: documentation


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V5.45.0 (August 8, 2022)
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* New: improvements for MIDI

* Chg: TL-Installer 1.27

* Chg: API functions TUSBAUDIO_GetASIOInstanceCount and TUSBAUDIO_GetASIOInstanceDetails now loads the ASIO configuration,
       call TUSBAUDIO_EnumerateDevices before is not required anymore

* Chg: documentation


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V5.40.0 (May 5, 2022)
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* New: multiple ASIO instances are now handled

* New: control panel supports multiple ASIO instances

* New: several registry parameters added

* New: new API version 5.9, some API functions added

* New: Installer now MSI based

* Fix: ASIO did not work if device is connected with invalid clock and 
       than switched to a valid clock

* Chg: volume control names can be configured in the control panel

* Chg: Documentation


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V5.30.0 (December 1, 2021)
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* New: support for Windows 10 (21H2)

* Fix: problem with only one MIDI direction

* Fix: scaling issues in control panel

* Chg: some improvements for MIDI

* Chg: sample rate recovery improved

* Chg: Documentation


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V5.27.0 (October 19, 2021)
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* Fix: fixed a security vulnerability (update recommended)

* Chg: DspPlugin (Mixer) now works with IN or OUT only devices


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V5.25.0 (October 4, 2021)
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* New: support for Windows 11 (21H2)

* New: tested with HLK for Windows 11 on W11 version 21H2

* Chg: improved tracing/statistics

* Chg: now using SignTools 1.9

* Fix: possible infinite loop in MIDI RX


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V5.20.0 (June 28, 2021)
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* New: support for Windows 10 (21H1)

* New: audio class 1.0: extract channel names from input terminal descriptor iChannelNames field

* New: API version 5.8

* Fix: initialization of auto stream format selection was missing

* Chg: Audio control interface for MIDI is optional

* Chg: Operating systems Windows 7, Windows 8 and Windows 8.1 are not longer supported 
              (Microsoft discontinued vendor signing)

* Chg: Documentation


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V5.12.0 (May 18, 2021)
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* New: MIDI pipe statistics in the Spy utility

* New: several registry parameters for MIDI added 

* Fix: switch preferred ASIO buffer size with driver package containing MIDI only and audio devices

* Chg: MIDI RX now uses USB flow control

* Chg: improved ISO packet error check

* Chg: scripts use Python 3.9.1 now

* Chg: DCK needs Windows 10 now

* Chg: documentation

* Chg: one channel can be part of more than 4 sound devices now


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V5.0.0 (December 04, 2020)
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* New: support for Windows 10 (2009/20H2)

* Fix: "ExposeToAsio" registry value in VirtualChannelProfiles

* New: API version 5.7, some API functions added

* New: several registry parameters added

* New: WDM sound device profile switching

* New: hardware channels can be hidden now

* New: USB audio float format support

* New: ASIO DLL now supports "AsioHide" parameter

' New: ASIO future extension allows to get access to hidden channels

* Chg: reduced default StreamingBufferMaxDuration from 4ms to 1ms

* Chg: documentation


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V4.86.0 (June 19, 2020)
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* New: support for Windows 10 (2004/VB)

* New: Added API function TUSBAUDIO_GetExtendedInfo,
       API version 5.5

* New: optimized performance of the optional DSP mixer plugin

* New: ASIO extension to report device details: thesycon_asio_ext_usb.h

* Chg: fixed ASIO to USB buffer count mapping

* Chg: avoid stop raise condition in ASIO DLL if buffer switch consumes 100% CPU load

* Chg: TUSBAudioDfu utility: added *.tlimg to the DFU file open dialog

* Chg: ASIO position jumps forward if a drop out occurred.
       So position always reflects device stream position.

* Chg: After a dropout occurred, ASIO buffer switch callbacks 
       will not be issued in a loop to catch up, instead missed 
       callbacks will simply be skipped.

* Chg: converted to VS2019 project files (SDK)


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V4.82.0 (January 16, 2020)
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* Fix: XMOS firmware detection for DFU update

* Fix: KS child PDO hardware ID does not include REV code


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V4.80.0 (December 02, 2019)
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* New: support for Windows 10 (1909/19H2)

* New: added mixer app channel count limit and make it configurable through .xml file

* New: added additional optional driver interface GUID

* New: added sample rate selection page in control panel app

* New: registry parameter AllowSampleRateSwitchPerApiIfAsioIsActive

* New: Added API function TUSBAUDIO_GetControlPanelOptions,
       API version 5.4

* New: added support for Audio Class 1.0 notification endpoint (e.g. volume/mute changes),
       API version 5.3

* New: added UAC1DefaultSampleRate registry parameter to define default sample rate for Audio Class 1.0 device

* Fix: for Audio Class 1.0 devices streaming did not start after power down / power up

* Chg: Audio Class 1.0 notification endpoint handler now sends a GET_STAT or GET_MEM request

* Chg: Windows shows an error message if sample rate cannot be set 
       because another sound device which depends on the same 
       clock source is currently in use
       
* Chg: added DFUProtocol registry parameter

* Chg: DFU now works with different PIDs in application and DFU mode

* Chg: DFU detach request now supported

* Chg: DFU application now supports different target index values ("TargetIndex" attribute in .xml file)

* Chg: increased DFU timeout from 5 seconds to 30 seconds


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V4.67.0 (May 21, 2019)
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* New: support for Windows 10 (1903/19H1)

* Chg: Scripts use Python 3.7.3 now

* New: added latency reported by the device latency control to the Spy tool statistics

* New: Added registry key for unit configuration

* New: Added ASAltSettingsMaskIn, ASAltSettingsMaskOut, 
       UAC1SendSetSampleRateIn and UAC1SendSetSampleRateOut registry parameters

* New: added registry configuration parameter CreateSoundDevicesInDsdMode

* Chg: Added KsSampleRateControl registry parameter to configure how the KS sound devices are build

* Chg: Added SetInterfaceRequestTimeout registry parameter to configure timeout for USB SET_INTERFACE request

* Fix: TUSBAUDIO_SetSampleRate() and TUSBAUDIO_SetCurrentClockSource()
       fail if no streaming interface is present

* Fix: device with no streaming interface leads to empty sample rate list

* Chg: no endian conversion for 64-bit DSD format (UAC3)

* New: native DSD format described in the user manual

* Chg: Prefer 64-bit DSD format (UAC3) over 32-bit DSD format (XMOS)

* New: Mixer API and documentation: TUsbAudioMixer.h

* New: Mixer app refactored to integrate new API and 
       implement separate dialogs for Full and Simple layout

* Fix: Mixer app crashes when device is removed while
       level pop-up dialog is open


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V4.59.0 (January 17, 2019)
-----------------------------------------------------

* New: support for Windows 10 (1809/RS5)

* New: support clock selector notifications from the the device

* New: sound device configuration now allows use of the same physical channel in different sound devices in parallel

* Fix: problem in KS MIDI processing function

* Fix: TUSBAUDIO_QueryDeviceStatistics can cause the calling app to crash

* Chg: build environment switched to Visual Studio 2017 with WDK 1709

* Chg: documentation


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V4.55.0 (November 09, 2018)
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* Fix: ASIO device selection does not work on some systems

* Fix: default sound device creation algorithm created an empty format list


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V4.54.0 (November 06, 2018)
-----------------------------------------------------

* Fix: descriptor parser reads from a position past descriptor limit 
       if the device implements a MIDI AC only

* Fix: bring ASIO settings dialog in foreground does not work in all cases

* Chg: upgraded to ASIO SDK 2.3.1

* Fix: overwriting feature unit ID does not work correctly

* Chg: added mixer control panel customization options

* Fix: propose format property overrides other properties

* Chg: added registry keys MaxBitsPerSample, Emulate16bitFormat and Emulate24bitFormat per sound device

* Fix: feature unit override per registry does not support master channel

* Chg: removed per-channel registry settings VolumeControl and MuteControl

* Chg: added MinSampleRate and MaxSampleRate registry parameter to Windows sound device configuration


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V4.47.0 (July 31, 2018)
-----------------------------------------------------

* Chg: QPC runtime measurement added again

* Fix: Spy tool doesn't work correctly with virtual channels

* Chg: improved Spy tool statistics

* Chg: API version 5.2

* New: API function TUSBAUDIO_QueryDeviceStatistics added


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V4.46.0 (July 24, 2018)
-----------------------------------------------------

* New: Workaround for driver unload problems (Code 38 in device manager)
       caused by KS layer leaking references on our child PDO.
       Registry parameter EnableLeakedPdoRefsWorkaround (true by default)

* New: Added optional PreferDeviceInfo to the KS .inf to use string descriptor of
       the audio control interface if exists or product string of the device
       for device description instead of the one from the .inf file

* Fix: Crash occurs if feature unit is specified explicitly via .inf file

* Fix: Linker optimization eliminated gDriverVersionString which we want to keep in the .sys


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V4.45.0 (June 18, 2018)
-----------------------------------------------------

* New: support for Windows 10 (1803/RS4)

* Chg: volume input/output channel names now customizable in control panel

* Chg: ASIO device is now selectable, new API functions:
       TUSBAUDIO_SetPreferredASIODevice, TUSBAUDIO_ClearPreferredASIODevice
       
* Fix: volume control for device with master only control was not working


* Fix: sound device name, visible via DirectKS now uses the string from the USB terminal/control interface


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V4.43.0 (March 28, 2018)
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* New: added DisableGetProposeDataFormatIN and DisableGetProposeDataFormatOUT
       registry parameter to disable GetProposeDataFormat handler in KS
       
* New: added registry parameter to configure default sound device category and name
       (DefaultSoundDeviceIN and DefaultSoundDeviceOUT)


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V4.42.0 (March 22, 2018)
-----------------------------------------------------

* Fix: processing did not recover correctly from stream errors

* Fix: BSOD in KS driver error handling

* Fix: DSP load mixer weights ignores default initialization

* Fix: DSP mixer weights not saved in registry on system reboot

* Fix: auto mode with alternate settings containing different channel counts and
       USB valid alternate setting request supported by the device


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V4.41.0 (February 15, 2018)
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* New: Emulate16bitFormatIn/Out and Emulate24bitFormatIn/Out config settings

* New: DSD stream format defined in the USB audio class 3.0 is supported,
       see Frmts30.pdf, section 2.3.1.6.5

* New: VALID_ALT_SETTINGS control is used (if implemented by the device)
       to auto-select alt setting based on sample rate

* New: VALID_ALT_SETTINGS control notifications supported,
       notification triggers stream restart and ASIO reset
       
* Fix: automatic alternate setting selection mode didn't work in all case
       if the device has external clock sources


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V4.40.0 (January 25, 2018)
-----------------------------------------------------

* Fix: level meter for virtual channels didn't work correctly in the mixer application

* Fix: cleanup if DriverEntry fails

* Fix: software loopback path issue in DSP plugins


* Chg: Windows mono recording devices now show full list of formats

* Chg: volume controls for an odd number of channels are now shown in the control panel


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V4.38.0 (December 05, 2017)
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* Fix: mixer app weight update issue


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V4.37.0 (November 30, 2017)
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* New: support for Windows 10 (1709/RS3)

* Fix: sound devices with virtual channels are not shown

* Chg: Microsoft signing now with symbols (DCK)


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V4.36.0 (November 08, 2017)
-----------------------------------------------------

* Chg: removed Company from version resources

* Fix: GetProposeDataFormat now reports 2 channels for speaker device to work again
       with speaker sound devices with more than 8 channels


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V4.35.0 (October 26, 2017)
-----------------------------------------------------

* Fix: reported current sample rate for Audio Class 1.0 device was not correct

* Fix: 32bit ASIO DLL was not registered on 64bit systems (introduced in 4.34)


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V4.34.0 (October 16, 2017)
-----------------------------------------------------

* Chg: added sample rate unit string for status page and changed sample rate strings

* Chg: ASIO DLL now optional in DCK scripts

* Fix: default ASIO channel names begins with index 1 instead of 0

* Fix: control panel clock source poll timer kill exception


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V4.33.0 (October 11, 2017)
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* Fix: customized strings are not shown correctly in the control panel and DFU app

* Chg: python scripts of the DCK now support pathnames longer than 260 characters


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V4.32.0 (October 10, 2017)
-----------------------------------------------------

* Chg: statistics extended

* Chg: ASIO switch IOCTL optimized

* Fix: ASIO reset loop if buffer switch is blocked

* Fix: ASIO DLL internal settings struct was not synchronized


-----------------------------------------------------
V4.30.0 (September 29, 2017)
-----------------------------------------------------

* New: sample rates higher 192kHz now supported on Windows 7 for WASAPI exclusive mode applications

* New: ASIO to USB buffer size mappings now can be configured through registry

* Chg: external clock source handling changed, clock source notifications now supported

* New: registry option ClockSourceSupportsNotifications

* New: API function TUSBAUDIO_GetClockSourceStatus

* New: notification NotifyEvent_AsioBufferSizeChanged added

* New: ASIO channel setup now can be configured through registry

* Chg: language customization format of control panel and DFU application changed

* New: added MinAsioBufferSize_48k and MaxAsioBufferSize_48k registry parameters
       to limit the ASIO buffer size

* Chg: USB interface blocking is supported in device instance registry key only, 
       not in service key, iAP interface will be blocked by default

* New: user manual significantly improved and enhanced

* Chg: ASIO now reports a range of buffer sizes (can be disabled through registry key)

* Fix: ASIO thread priority now set before first ASIO buffer switch

* Fix: current ISO buffer was not released in stop stream

* New: two different ASIO buffer size modes:
       - multiply ASIO buffer size if sample rate is changed
       - constant ASIO buffer size if sample rate is changed
       
* New: added optional additional USB out buffer to full-fill Ableton Live CPU load simulator
       (this adds extra latency to the OUT path if enabled)
       
* New: added script support for APOs
     
* Chg: streaming buffer size change does no longer destroy and recreate child PDO
       and MIDI ports (dynamic MIDI ports cannot be handled by all apps properly)

* Chg: increased ASIO thread priority to 26

* New: added kThesyconAsioSetThreadBasePrio ASIO future request

* Fix: volume control slider in control panel was not always in correct position

* Chg: include USB product string in default MIDI names

* New: 384k and 352.8k sample rate supported on Win10

* Chg: registry parameter Disable200kHzLimit removed

* New: support for Windows 10 (1703/RS2)

* New: device latency now can be overwritten through registry

* Chg: ASIO implementation improved: latency reduced by one ASIO buffer size

* Chg: ASIO buffer setting redesigned, USB buffer setting removed

* Chg: API function TUSBAUDIO_GetUsbStreamingMode, TUSBAUDIO_SetUsbStreamingMode, TUSBAUDIO_GetMinimumASIOBufferSize,
       TUSBAUDIO_GetASIOBufferSize and TUSBAUDIO_SetASIOBufferSize removed
       
* New: API function TUSBAUDIO_GetASIOInstanceInfo and TUSBAUDIO_SetASIOBufferPreferredSize added


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V4.14.0 (September 06, 2017) 
-----------------------------------------------------

* Chg: added registry key to reject lower channel counts on WDM sound devices


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V4.13.0 (July 19, 2017) 
-----------------------------------------------------

* Chg: implemented get KSPROPERTY_PIN_PROPOSEDATAFORMAT handler in KS driver


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V4.12.0 (June 29, 2017) 
-----------------------------------------------------

* New: Installer: code integrity check during installation

* Chg: INF file DriverVer date/time now reflects the time when the driver 
       package was built

* Chg: Installer setup.ini uses attestation signed package for Server 2016

* New: Installer supports automatic uninstallation of other driver packages via 
       setup.ini option AdditionalSetupRegPathList

* New: Installer supports custom icon shown in Apps&Features panel via
       setup.ini option CustomUninstallIcon


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V4.11.0 (May 03, 2017) 
-----------------------------------------------------

* Fix: BSOD if a device implements a playback path only and no recording path

* Fix: bug in time bomb restriction: potential infinite loop

* New: IgnoreInPath/IgnoreOutPath/IgnoreFeedbackEndpoint registry 
       parameters (used for testing purposes only)


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V4.10.0 (April 26, 2017) 
-----------------------------------------------------

* New: Workaround for "Unknown publisher" warning pop-up
       in uninstall panel in Windows 10


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V4.0.0 (April 24, 2017) 
-----------------------------------------------------

* Chg: Thesycon handles full customization by default,
       DSK and DCK available to customers

* Chg: Driver uses new license mechanism

* Fix: Conversion of 32 bit pointers in the x64 driver in case 
       a 32 bit application uses /LARGEADDRESSAWARE

* Chg: Installer setup.ini supports separate driver packages for
       Win7 and Win10, required for new signing requirement
       
* Chg: Driver package now contains 32bit and 64bit API DLLs on 64bit systems

* New: Registry parameters DisableKsVolMuteIn and DisableKsVolMuteOut

* Chg: Debug driver uses ETW based debug traces now (requires tracecon.exe utility)
