AVS Device SDK Release Notes

This page contains release information about the Alexa Voice Service (AVS) Device SDK, including feature enhancements, updates, and resolved issues.

Version 1.18.0 - February 19 2020


Bug fixes

  • Fixed Mac/OSX issue that caused an unresponsive Sample App when not connected to the internet.
  • Fixed issue that prevented sample app from exiting various states.
  • Fixed UIManager issue that caused an error in the logs when the device with built without the wake word enabled.
  • Fixed volume issue that caused timers to ascend in volume when setting up ascending alarms.
  • Fixed alert volume issue that caused any changes to the alert volume to notify observers.
  • Fixed EQ issue where changes to the EQ band levels didn't notify observers.

Known Issues

  • Build errors can occur on the Raspberry Pi due to incorrect linking of the atomic library. A suggested workaround is to add the following set(CMAKE_CXX_LINK_FLAGS "${CMAKE_CXX_LINK_FLAGS} -latomic") to the top most CMake file.
  • The WebVTT dependency required for captions isn't supported for Windows/Android.
  • Exiting from the setting option takes you back to the Options Menu directly. It doesn't provide a message to indicate that you're back in the main menu.
  • Failing Unit Tests and AIP Unit tests are disabled on Windows
  • AudioInputProcessor unit tests don't build on Windows when with the -DCMAKE_BUILD_TYPE=DEBUG cmake parameter.
  • Music playback history isn't displayed in the Alexa app for certain account and device types.
  • When using Gnu Compiler Collection 8+ (GCC 8+), -Wclass-memaccess triggers warnings. You can ignore these, they don't cause the build to fail.
  • Android error libDefaultClient.so not found might occur. Resolve this problem by upgrading to ADB version 1.0.40.
  • If a device loses a network connection, the lost connection status isn't returned though local TTS.
  • ACL encounters issues if it receives audio attachments but doesn't consume them.
  • Media streamed through Bluetooth might abruptly stop. To restart playback, resume the media in the source application or toggle next/previous.
  • If a connected Bluetooth device is inactive, the Alexa app might indicates that audio is playing.
  • The Bluetooth agent assumes that the Bluetooth adapter is always connected to a power source. Disconnecting from a power source during operation isn't yet supported.
  • When using some products, interrupted Bluetooth playback might not resume if other content is locally streamed.
  • make integration isn't available for Android. To run Android integration tests, manually upload the test binary and input file and run ADB.
  • Alexa might truncate the beginning of speech when responding to text-to-speech (TTS) user events. This only impacts Raspberry Pi devices running Android Things with HDMI output audio.
  • A reminder TTS message doesn't play if the sample app restarts and loses a network connection. Instead, the default alarm tone plays twice.
  • ServerDisconnectIntegratonTest tests are disabled until they are updated to reflect new service behavior.
  • The DirectiveSequencerTest.test_handleBlockingThenImmediatelyThenNonBockingOnSameDialogId test fails intermittently.

Version 1.17.0 - December 10 2019


  • Added support for captions for TTS. This enhancement allows you to print on-screen captions for Alexa voice responses.
  • Added support for SpeechSynthesizer Interface 1.3. This interface supports the new captions parameter.
  • Added support for AudioPlayer Interface 1.3. This interface supports the new captions parameter.
  • Added support for Interaction Model 1.2.
  • Added support for System 2.0.
  • Added support for Alerts Interface 1.4.
  • Added support for Alarm Volume Ramp (Ascending Alarms in the Companion App). This feature lets the user enable alarm fade in. You enable this feature in the sample app through the settings menu.
  • Added support to use certified senders for URI path extensions. This change allows you to specify the URI path extension when sending messages with CertifiedSender::sendJSONMessage
  • Added new Metrics interfaces and helper classes. These additions help you create and consume Metrics events.
    • Interfaces - MetricRecorderInterface, MetricSinkInterface.
    • Helper Classes - DataPointStringBuilder, DataPointCounterBuilder, DataPointDurationBuilder, MetricEventBuilder.
  • Added support for the following AVS endpoint controller capabilities:
  • Added PowerResourceManagerInterface. This interface allows the SDK to control power resource levels for components such as the AudioInputProcessor and SpeechSynthesizer.
  • Added AlexaInterfaceCapabilityAgent. This Capability Agent handles common directives and endpoint controller capabilities support by Alexa.AlexaInterface.
  • Added AlexaInterfaceMessageSenderInterface. Use this interface to send common events defined by the Alexa.AlexaInterface interface.
  • Added BufferingComplete to MediaPlayerObserverInterface. This method helps improve performance in poor networking conditions by making sure MediaPlayer pre-buffers correctly.
  • Added SendDTMF to CallManagerInterface. This method allows you to send DTMF tones during calls.

New build options

New dependencies

  • To use captions, you must install a new dependency – the libwebvtt parsing library. WebVTT is a C/C++ library for interpreting and authoring WebVTT content. WebVTT is a caption and subtitle format designed for use with HTML5 audio and video elements.

Bug fixes

Known Issues

  • The WebVTT dependency required for captions isn't supported for Windows/Android.
  • AudioInputProcessor unit tests don't build on Windows when with the -DCMAKE_BUILD_TYPE=DEBUG cmake parameter.
  • Music playback history isn't displayed in the Alexa app for certain account and device types.
  • When using Gnu Compiler Collection 8+ (GCC 8+), -Wclass-memaccess triggers warnings. You can ignore these, they don't cause the build to fail.
  • Android error libDefaultClient.so not found might occur. Resolve this by upgrading to ADB version 1.0.40.
  • If a device loses a network connection, the lost connection status isn't returned through local TTS.
  • ACL encounters issues if it receives audio attachments but doesn't consume them.
  • SpeechSynthesizerState uses GAINING_FOCUS and LOSING_FOCUS as a workaround for handling intermediate states.
  • Media streamed through Bluetooth might abruptly stop. To restart playback, resume the media in the source application or toggle next/previous.
  • If a connected Bluetooth device is inactive, the Alexa app might indicates that audio is playing.
  • The Bluetooth agent assumes that the Bluetooth adapter is always connected to a power source. Disconnecting from a power source during operation isn't yet supported.
  • When using some products, interrupted Bluetooth playback might not resume if other content is locally streamed.
  • make integration isn't available for Android. To run Android integration tests, manually upload the test binary and input file and run ADB.
  • Alexa might truncate the beginning of speech when responding to text-to-speech (TTS) user events. This only impacts Raspberry Pi devices running Android Things with HDMI output audio.
  • A reminder TTS message doesn't play if the sample app restarts and loses a network connection. Instead, the default alarm tone plays twice.
  • ServerDisconnectIntegratonTest tests are disabled until they are updated to reflect new service behavior.
  • The DirectiveSequencerTest.test_handleBlockingThenImmediatelyThenNonBockingOnSameDialogId test fails intermittently.
  • On some devices, Pressing t and h in the Sample App doesn't exit the assigned state.
  • Exiting the settings menu doesn't provide a message to indicate that you're back in the main menu.

Version 1.16.0 - October 25 2019


  • Added support for SpeechSynthesizer version 1.2 which includes the new playBehaviour directive.
  • Added support for pre-buffering in the AudioPlayer Capability Agent. You can optionally choose the number of instances MediaPlayer uses in the AlexaClientSDKconfig.json. Important: the contract for MediaPlayerInterface has changed. You must now make sure that the SourceId value returned by setSource() is unique across all instances.
  • The AudioPlayer Capability Agent is now licensed under the Amazon Software License instead of the Apache Software License.

Bug Fixes

  • Fixed Android issue that caused the build script to ignore PKG_CONFIG_PATH. This sometimes caused the build to use a preinstalled dependency instead of the specific version downloaded by the Android script. For example openssl).
  • Fixed Android issue that prevented the Sample app from running at the same time as other applications using the microphone. Android doesn't inherently allow two applications to use the microphone. Pressing the mute button now temporarily stops Alexa from accessing the microphone.
  • Added 'quit' (– q) to the settings sub menu.
  • Fixed outdated dependencies issue in the Windows install script.
  • Fixed reminders issue that caused Notification LEDs to stay on, even after dismissing the alert.

For more details, check this.

Version 1.15.0 - September 25 2019


  • Added SystemSoundPlayer to ApplicationUtilities . SystemSoundPlayer is a new class that plays pre-defined sounds. Supported sounds include the wake word notification and the end of speech tone.
  • Removed Echo Spatial Perception (ESP) functionality from the Alexa Voice Service (AVS) device SDK. Make sure you download and test your devices using the new AVS SDK sample app. If you're using an older version of the sample app, manually remove any references to ESP or errors occur during compile.
  • Added onNotificationReceived to NotificationsObserverInterface. onNotificationReceived broadcasts when NotificationsObserverInterface receives a new notification, instead of only sending the indicator state. This is important if you support a feature that requires a distinct signal for each notification received. See NotificationsObserverInterface for more details.
  • Added support for Multilingual Mode . With this enabled, Alexa automatically detects what language a user speaks by analyzing the spoken wake word and proceeding utterances. Once Alexa identifies the language, all corresponding responses are in the same language. The current supported language pairs are:
  • [ "en-US", "es-US" ]
  • [ "es-US", "en-US" ]
  • [ "en-IN", "hi-IN" ]
  • [ "hi-IN", "en-IN" ]
  • [ "en-CA", "fr-CA" ]
  • [ "fr-CA", "en-CA" ]

    IMPORTANT: Specify the locales your device supports in the localeCombinations field in AlexaClientSDKConfig.json. This field can't be empty. If you don't set these values, the sample app fails to run.
  • Added two new system settings, Timezone and Locale.
    • Timezone: For example, you can set the defaultTimezone to America/Vancouver. If you don't set a value, GMT is set as the default value. If you set a new timezone, make sure that your AVS system settings and default time zone stay in sync. To handle this, use the new class SystemTimeZoneInterface.
    • Locale: For example, you can set defaultLocale to en-GB, instead of the default en-US.
  • The SpeechRecognizer interface now supports the following functionalities.
    • Change wake word (Alexa supported for now).
    • Toggle start of request tone on/off.
    • Toggle End of request tone on/off.
  • Deprecated the CapabilityAgents Settings{…} library. Settings {…} now maps to an interface that's no longer supported. You might need to update your code to handle these changes. Read Settings Interface for more details.
  • Added support for three new locals: Spanish - United States (ES_US), Hindi - India (HI_IN), and Brazilian - Portuguese (PT_BR).
  • Linked the atomic library to the sample app to prevent build errors on Raspberry Pi.

Bug Fixes

  • Fixed resource leaking in EqualizerCapabilityAgent after engine shutdown.
  • Issue 1391: Fixed an issue where SQLiteDeviceSettingsStorage::open tries to acquire a mutex twice, resulting in deadlock.
  • Issue 1468: Fixed a bug in AudioPlayer::cancelDirective that causes a crash.
  • Fixed Windows install script that caused the sample app build to fail. removed pip, flask, requests, and commentjson dependencies from the mingw.sh helper script.
  • Fixed issue: notifications failed to sync upon device initialization. For example, let's say you had two devices. one turned on and the other turned off. After clearing the notification on the first device, it still showed up on the second device after turning it on.
  • Fixed issue: barging in on a reminder caused it to stick in an inconsistent state, blocking subsequent reminders. For example, if a reminder was going off and you interrupted it, the reminder would get persist indefinitely. You could schedule future reminders, but they wouldn't play. Saying “Alexa stop” or rebooting the device fixed the “stuck” reminder.

Version 1.14.0 - July 09 2019


  • AudioPlayer can now pre-buffer audio tracks in the Pre-Handle stage.

Bug Fixes

  • Fixed an issue in the SQLite wrapper code where a SQLiteStatement caused a memory corruption issue.
  • Fixed a race condition in SpeechSynthesizer that caused crashes.
  • Fixed a cmake issue that specifies a dependency for Bluetooth incorrectly.
  • Fixed a bug that caused Bluetooth playback to start automatically.
  • Changed supportedOperations from a vector to a set in ExternalMediaAdapterInterface.
  • Corrected an issue where a VolumeChanged event had previously been sent when the volume was unchanged after setVolume or adjustVolume had been called locally.
  • Fixed issue with IterativePlaylistParser that prevented live stations on TuneIn from playing on Android.
  • Corrected the spelling of "UNINITIALIZED".

Version 1.13.0 - May 22 2019


  • When an active Alert moves to the background, the alert now begins after a 10-second delay. Alert loop iteration delays can now no longer last longer than a maximum of 10 seconds, rather than depending on the length of the audio asset.
  • Changed NotificationsSpeaker to use Alerts Volume instead of using the speaker volume.
  • Allow customers to pass in an implementation of InternetConnectionMonitorInterface which will force AVSConnectionManager to reconnect on internet connectivity loss.
  • Added an exponential wait time for retrying transmitting a message via CertifiedSender.
  • When Volume is set to 0 and device is unmuted, volume is bumped up to a non-zero value. When Volume is set to 0 and Alexa talks back to you, volume is bumped up to a non-zero value.
  • Deprecated HttpResponseCodes.h, which is now present only to ensure backward compatibility.
  • The default base URLs for AVS have changed. These new URLs are supported by SDK v1.13 and later versions. Amazon recommends that all new and existing implementations update to v1.13 or later and use the new base URLs accordingly; however, Amazon will continue to support the legacy base URLs.

Bug Fixes

  • Fixed bug where receiving a Connected = true Property change from BlueZ without UUID information resulted in BlueZBluetoothDevice transitioning to CONNECTED state.
  • Fixed bug where MediaStreamingStateChangedEvent may be sent on non-state related property changes.
  • Added null check to SQLiteStatement::getColumnText.
  • Fixed an issue where database values with unescaped single quotes passed to miscStorage database will fail to be stored. Added a note on the interface that only non-escaped values should be passed.
  • Fixed a loop in audio in live stations based on playlists.
  • Fixed a race condition in TemplateRuntime that may result in a crash.
  • Fixed a race condition where a recognize event due to a EXPECT_SPEECH may end prematurely.
  • Changed the name of Alerts channel to Alert channel within AudioActivityTracker.
  • Prevented STOP Wakeword detections from generating Recognize events.
  • The SQLiteDeviceSettingsStorageTest no longer fails for Android.

Version 1.12.1 - April 02 2019

Bug Fixes

  • Fixed a bug where the same URL was being requested twice when streaming iHeartRadio. Now, a single request is sent.
  • Corrected pause/resume handling in ProgressTimer so that extra ProgressReportDelayElapsed events are not sent to AVS.

Version 1.12.0 - February 25 2019


  • Support was added for the fr_CA locale.
  • The Executor has been optimized to run a single thread when there are active job in the queue, and to remain idle when there are not active jobs.
  • An additional parameter of alertType has been added to the Alerts capability agent. This will allow observers of alerts to know the type of alert being delivered.
  • Support for programmatic unload and load of PulseAudio Bluetooth modules was added. To enable this feature, there is a new CMake option : BLUETOOTH_BLUEZ_PULSEAUDIO_OVERRIDE_ENDPOINTS. Note that libpulse-dev is a required dependency of this feature.
  • An observer interface was added for when an active Bluetooth device connects and disconnects.
  • The BluetoothDeviceManagerInterface instantiation was moved from DefaultClient to SampleApp to allow applications to override it.
  • The MediaPlayerInterface now supports repeating playback of URL sources.
  • The Kitt.AI wake word engine (WWE) is now compatible with GCC5+.
  • Stop of ongoing alerts, management of MessageObservers, and management of CallStateObservers have been exposed through DefaultClient.

Bug Fixes

  • Issue 953 - The MediaPlayerInterface requirement that callbacks not be made upon a callers thread has been removed.
  • Issue 1136 - Added a missing default virtual destructor.
  • Issue 1140 - Fixed an issue where DND states were not synchronized to the AVS cloud after device reset.
  • Issue 1143 - Fixed an issue in which the SpeechSynthesizer couldn't enter a sleeping state.
  • Issue 1183 - Fixed an issue where alarm is not sounding for certain time zones
  • Changing an alert's volume from the Alexa app now works when an alert is playing.
  • Added missing shutdown handling for ContentDecrypter to prevent the Stop command from triggering a crash when SAMPLE-AES encrypted content was streaming.
  • Fixed a bug where if the Notifications database is empty, due to a crash or corruption, the SDK initialization process enters an infinite loop when it retries to get context from the Notifications capability agent.
  • Fixed a race condition that caused AlertsRenderer observers to miss notification that an alert has been completed.

Version 1.11.0 - December 19 2018


  • Added support for the new Alexa DoNotDisturb interface, which enables users to toggle the do not disturb (DND) function on their Alexa built-in products.
  • The SDK now supports Opus encoding, which is optional. To enable Opus, you must set the CMake flag to -DOPUS=ON , and include the libopus library dependency in your build.
  • The MediaPlayer reference implementation has been expanded to support the SAMPLE-AES and AES-128 encryption methods for HLS streaming.
    • AES-128 encryption is dependent on libcrypto, which is part of the required openSSL library, and is enabled by default.
    • To enable SAMPLE-AES encryption, you must set the -DSAMPLE_AES=ON in your CMake command, and include the FFMPEG library dependency in your build.
  • A new configuration for deviceSettings has been added. This configuration allows you to specify the location of the device settings database.
  • Added locale support for es-MX.

Bug Fixes

  • Fixed an issue where music wouldn't resume playback in the Android app.
  • Now all equalizer capabilities are fully disabled when equalizer is turned off in configuration file. Previously, devices were unconditionally required to provide support for equalizer in order to run the SDK.
  • Issue 1106 - Fixed an issue in which the CBLAuthDelegate wasn't using the correct timeout during request refresh.
  • Issue 1128 - Fixed an issue in which the AudioPlayer instance persisted at shutdown, due to a shared dependency with the ProgressTimer.
  • Fixed in issue that occurred when a connection to streaming content was interrupted, the SDK did not attempt to resume the connection, and appeared to assume that the content had been fully downloaded. This triggered the next track to be played, assuming it was a playlist.
  • Issue 1040 - Fixed an issue where alarms would continue to play after user barge-in.

Version 1.10.0 - October 24 2018


  • New optional configuration for EqualizerController . The EqualizerController interface allows you to adjust equalizer settings on your product, such as decibel (dB) levels and modes.
  • Added reference implementation of the EqualizerController for GStreamer-based (MacOS, Linux, and Raspberry Pi) and OpenSL ES-based (Android) MediaPlayers. Note: In order to use with Android, it must support OpenSSL ES.
  • New optional configuration for the TemplateRuntime display card value .
  • A configuration file generator script, genConfig.sh is now included with the SDK in the tools/Install directory. genConfig.sh and it's associated arguments populate AlexaClientSDKConfig.json with the data required to authorize with LWA.
  • Added Bluetooth A2DP source and AVRCP target support for Linux.
  • Added Alexa for Business (A4B) support, which includes support for handling the new RevokeAuthorization directive in the Settings interface. A new CMake option has been added to enable A4B within the SDK, -DA4B.
  • Added locale support for IT and ES.
  • The Alexa Communication Library (ACL), CBLAUthDelegate, and sample app have been enhanced to detect de-authorization using the new z command.
  • Added ExternalMediaPlayerObserver, which receives notification of player state, track, and username changes.
  • HTTP2ConnectionInterface was factored out of HTTP2Transport to enable unit testing of HTTP2Transport and re-use of HTTP2Connection logic.

Bug Fixes

  • Fixed a bug in which ExternalMediaPlayer adapter playback wasn't being recognized by AVS.
  • Issue 973 - Fixed issues related to AudioPlayer where progress reports were being sent out of order or with incorrect offsets.
  • An EXPECTING, state has been added to DialogUXState in order to handle EXPECT_SPEECH state for hold-to-talk devices.
  • Issue 948 - Fixed a bug in which the sample app got stuck in various states.
  • Fixed a bug where there was a delay between receiving a DeleteAlert directive, and deleting the alert.
  • Issue 839 - Fixed an issue where speech was being truncated due to the DialogUXStateAggregator transitioning between a THINKING and IDLE state.
  • Fixed a bug in which the AudioPlayer attempted to play when it wasn't in the FOREGROUND focus.
  • CapabilitiesDelegateTest now works on Android.
  • Issue 950 - Improved Android Media Player audio quality.
  • Issue 908 - Fixed compile error on g++ 7.x in which includes were missing.

Version 1.9.0 - August 28 2018


  • Added Android SDK support, which includes new implementations of the MediaPlayer, audio recorder, and logger.
  • Added the InteractionModel interface, which enables Alexa Routines.
  • Optional configuration changes have been introduced. Now a network interface can be specified to connect to the SDK via curl.
  • Build options can be configured to support Android.
  • Added GUI 1.1 support. The PlaybackController has been extended to support new control functionality, and the System interface has been updated to support SoftwareInfo.

Bug Fixes

  • Installation script execution time has been reduced. Now a single branch clone is used, such as the master branch.
  • Issue 846 - Fixed a bug where audio stuttered on slow network connections.
  • Removed the SpeakerManager constructor check for non-zero speakers.
  • Issue 891 - Resolved incorrect offset in the PlaybackFinished event.
  • Issue 727 - Fixed an issue where the sample app behaved erratically upon network disconnection/reconnection.
  • Issue 910 - Fixed a GCC 8+ compilation issue. Note: issues related to -Wclass-memaccess will still trigger warnings, but won't fail compilation.
  • Issue 871 Issue 880 - Fixed compiler warnings.
  • Fixed an issue where PlaybackStutterStarted and PlaybackStutterFinished events were not being sent due to a missing Gstreamer queue element.
  • Fixed a bug where the CapabilitiesDelegate database was not being cleared upon logout.
  • Fixed in issue that caused the following compiler warning “class has virtual functions but non-virtual destructor”.
  • Fixed a bug where BlueZDeviceManager was not properly destroyed.
  • Fixed a bug that occurred when the initializer list was converted to std::unordered_set.
  • Fixed a build error that occurred when building with BUILD_TESTING=Off.

Version 1.8.1 - July 09 2018


  • Added support for adjustment of alert volume.
  • Added support for deletion of multiple alerts.
  • The following SpeakerInterface::Type enumeration values have changed:

Version 1.8.0 - June 27 2018


  • Added local stop functionality. This allows a user to stop an active function, such as an alert or timer, by uttering "Alexa, stop" when an Alexa-enabled product is offline.
  • Alerts in the background now stream in 10 sec intervals, rather than continuously.
  • Added support for France to the sample app.
  • Updated the ACL MIME type for sending JSON to AVS from "text/json" to "application/json".
  • friendlyName can now be updated for BlueZ implementations of BlueZBluetoothDevice and BlueZHostController.

Bug Fixes

  • Fixed an issue where the Bluetooth agent didn't clear user data upon reset, including paired devices and the uuidMapping table.
  • Fixed MediaPlayer threading issues. Now each instance has it's own glib main loop thread, rather than utilizing the default main context worker thread.
  • Fixed segmentation fault issues that occurred when certain static initializers needed to be initialized in a certain order, but the order wasn't defined.

Version 1.7.1 - May 04 2018


  • Added the Bluetooth interface, which manages the Bluetooth connection between Alexa-enabled products and peer devices. This release supports A2DP-SINK and AVRCP profiles. Note: Bluetooth is optional and is currently limited to Raspberry Pi and Linux platforms.
  • Added new Bluetooth dependencies for Linux and Raspberry Pi.
  • Device Capability Framework (DCF) renamed to Capabilities.
  • Updated the non-CBL client ID error message to be more specific.
  • Updated the sample app to enter a limited interaction mode after an unrecoverable error.

Bug Fixes

  • Issue 597 - Fixed a bug where the sample app did not respond to locale change settings.
  • Fixed issue where GStreamer 1.14 MediaPlayerTest failed on Windows.
  • Fixed an issue where a segmentation fault was triggered after unrecoverable error handling.

Version 1.7.0 - April 18 2018


  • AuthDelegate and AuthServer.py have been replaced by CBLAUthDelegate, which uses Code Based Linking for authorization.
  • Added new properties to AlexaClientSDKConfig:
    • cblAuthDelegate - This object specifies parameters for CBLAuthDelegate.
    • miscDatabase - A generic key/value database to be used by various components.
    • dcfDelegate - This object specifies parameters for DCFDelegate. Within this object, values were added for endpoint and overridenDcfPublishMessageBody. endpoint is the endpoint for the Capabilities API. overridenDcfPublishMessageBodyis the message that is sent to the Capabilities API. Note: Values in the dcfDelegate object will only work in DEBUG builds.
    • deviceInfo - Specifies device-identifying information for use by the Capabilities API and CBLAuthDelegate.
  • Updated Directive Sequencer to support wildcard directive handlers. This allows a handler for a given AVS interface to register at the namespace level, rather than specifying the names of all directives within a given namespace.
  • Updated the Raspberry Pi installation script to include alsasink in AlexaClientSDKConfig.
  • Added audioSink as a configuration option. This allows users to override the audio sink element used in Gstreamer.
  • Added an interface for monitoring internet connection status: InternetConnectionMonitorInterface.h.
  • The Alexa Communications Library (ACL) is no longer required to wait until authorization has succeeded before attempting to connect to AVS. Instead, HTTP2Transport handles waiting for authorization to complete.
  • Device capabilities can now be sent for each capability interface using the Capabilities API.
  • The sample app has been updated to send Capabilities API messages, which are automatically sent when the sample app starts. Note: A successful call to the Capabilities API must occur before a connection with AVS is established.
  • The SDK now supports HTTP PUT messages.
  • Added support for opt-arg style arguments and multiple configuration files. Now, the sample app can be invoked by either of these commands: SampleApp <configfile> <debuglevel> OR SampleApp -C file1 -C file2 ... -L loglevel.

Bug Fixes

  • Fixed Issues 447 and 553 .
  • Fixed the AttachmentRenderSource's handling of BLOCKING AttachmentReaders.
  • Updated the Logger implementation to be more resilient to nullptr string inputs.
  • Fixed a TimeUtils utility-related compile issue.
  • Fixed a bug in which alerts failed to activate if the system was restarted without network connection.
  • Fixed Android 64-bit build failure issue.

Version 1.6.0 - March 08, 2018


  • rapidJson is now included with "make install".
  • Updated the TemplateRuntimeObserverInterface to support clearing of displayCards.
  • Added Windows SDK support, along with an installation script (MinGW-w64).
  • Updated ContextManager to ignore context reported by a state provider.
  • The SharedDataStream object is now associated by playlist, rather than by URL.
  • Added the RegistrationManager component. Now, when a user logs out all persistent user-specific data is cleared from the SDK. The log out functionality can be exercised in the sample app with the new command: k.

Bug Fixes

  • Issue 400 Fixed a bug where the alert reminder did not iterate as intended after loss of network connection.
  • Issue 477 Fixed a bug in which Alexa's weather response was being truncated.
  • Fixed an issue in which there were reports of instability related to the Sensory engine. To correct this, the portAudio suggestedLatency value can now be configured.

Version 1.5.0 - February 12 2018


  • Added the ExternalMediaPlayer Capability Agent. This allows playback from music providers that control their own playback queue. Example: Spotify.
  • Added support for AU and NZ to the SampleApp.
  • Firmware version can now be sent to Alexa via the SoftwareInfo event. The firmware version is specified in the config file under the sampleApp object as an integer value named firmwareVersion .
  • The new f command was added to the SampleApp which allows the firmware version to be updated at run-time.
  • Optional configuration changes have been introduced. Now a default log level can be set for ACSDK_LOG_MODULE components, globally or individually. This value is specified under a new root level configuration object called logger, and the value itself is named logLevel. This allows you to limit the degree of logging to that default value, such as ERRORor INFO.

Bug Fixes

  • Fixed bug where AudioPlayer progress reports were not being sent, or were being sent incorrectly.
  • Issue 408 - Irrelevant code related to UrlSource was removed from the GStreamer-based MediaPlayer implementation.
  • The TZ variable no longer needs to be set to UTC when building the SampleApp.
  • Fixed a bug where CurlEasyHandleWrapper logged unwanted data on failure conditions.
  • Fixed a bug to improve SIGPIPE handling.
  • Fixed a bug where the filename and classname were mismatched. Changed UrlToAttachmentConverter.h to UrlContentToAttachmentConverter.h,and UrlToAttachmentConverter.cpp to UrlContentToAttachmentConverter.cpp.
  • Fixed a bug where after muting and then un-muting the GStreamer-based MediaPlayer implementation, the next item in queue would play instead of continuing playback of the originally muted item.


Version 1.4.0 - January 12 2018


  • Added the Notifications Capability Agent. This allows a client to receive notification indicators from Alexa.
  • Added support for the SoftwareInfo event. This code is triggered in the SampleApp by providing a positive decimal integer as the "firmwareVersion" value in "sampleApp" object of the AlexaClientSDKConfig.json. The reported firmware version can be updated after starting the SampleApp by calling SoftwareInfoSender::setFirmwareVersion(). This code path can be exercised in the SampleApp with the new command: f.
  • Added unit tests for Alerts.
  • The GStreamer-based pipeline allows for the configuration of MediaPlayer output based on information provided in Config.
  • Playlist streaming now uses a BLOCKING writer, which improves streaming efficiency.

Bug Fixes

  • Fixed bug where SpeechSynthesizer would not stop playback when a state change timeout was encountered.
  • Fixed the SampleApplication destructor to avoid segfaults if the object is not constructed correctly.
  • Fixed bug where AudioPlayer would erroneously call executeStop() in cancelDirective().
  • Issue 396 - Fixed bug for compilation error with GCC7 in AVSCommon/SDKInterfaces/include/AVSCommon/SDKInterfaces/Audio/AlertsAudioFactoryInterface.h
  • Issue 384 - Fixed bug that caused AuthServer.py to crash.
  • Fixed bug where a long delay was encountered after pausing and resuming a large Audible chapter.
  • Fixed bug that caused named timers and reminders to loop for an additional loopCount .
  • Fixed memory corruption bug in MessageInterpreter.
  • Fixed illegal memory accesses in MediaPlayer logging.

Version 1.3.0 - December 08 2017

  • Enhancements
    • ContextManager now passes the namespace/name of the desired state to StateProviderInterface::provideState(). This is helpful when a single StateProvider object provides multiple states, and needs to know which one ContextManager is asking for.
    • The mime parser was hardened against duplicate boundaries.
    • Added functionality to add and remove AudioPlayer observers to the DefaultClient.
    • Unit tests for Alerts were added.
    • Added en-IN, en-CA and ja-JP to the SampleApp locale selection menu.
    • Added default alert and timer audio data to the SDK SampleApp. There is no longer a requirement to download these audio files and configure them in the json configuration file.
    • Added support in SDS Reader and AttachmentReader for seeking into the future. This allows a reader to move to an index which has not yet arrived in the SDS and poll/block until it arrives.
    • Added support for blocking Writers in the SharedDataStream class.
    • Changed the default status code sent by MessageRequestObserverInterface::onSendCompleted() to SERVER_OTHER_ERROR, and mapped HTTP code 500 to SERVER_INTERNAL_ERROR_V2.
    • Added support for parsing stream duration out of playlists.
    • Added a configuration option ("sampleApp":"displayCardsSupported") that allows the displaying of display cards to be enabled or disabled.
    • Named Timers and Reminders have been updated to fall back to the on-device background audio sound when cloud urls cannot be accessed or rendered.
  • Bug Fixes
    • Removed floating point dependencies from core SDK libraries.
    • Fixed bug in SpeechSynthesizer where it's erroneously calling stop more than once.
    • Fixed an issue in ContentFetcher where it could hang during destruction until an active GET request completed.
    • Fixed a couple of parsing bugs in LibCurlHttpContentFetcher related to case-sensitivity and mime-type handling.
    • Fixed a bug where MediaPlayerObserverInterface::onPlaybackResumed() wasn't being called after resuming from a pause with a pending play/resume.
    • Fixed a bug in LibCurlContentFetcher where it could error out if data is written to the SDS faster than it is consumed.
    • The GStreamer-based MediaPlayer reference implementation now uses the ACL HTTP configured client.
      • An API change has been made to MediaPlayerInterface::setSource(). This method now takes in an optional offset as well to allow for immediately streaming to the offset if possible.
      • Next and Previous buttons now work with Audible.
      • Pandora resume stuttering is addressed.
      • Pausing and resuming Amazon music no longer seeks back to the beginning of the song.
    • libcurl CURLOPT_NOSIGNAL option is set to 1 (https://curl.haxx.se/libcurl/c/CURLOPT_NOSIGNAL.html) to avoid crashes observed in SampleApp.
    • Fixed the timing of the PlaybackReportIntervalEvent and PlaybackReportDelayEvent as specified in the directives.
    • Fixed potential deadlocks in MediaPlayer during shutdown related to queued callbacks.
    • Fixed a crash in MediaPlayer that could occur if the network is disconnected during playback.
    • Fixed a bug where music could keep playing while Alexa is speaking.
    • Fixed a bug which was causing problems with pause/resume and next/previous with Amazon Music.
    • Fixed a bug where music could briefly start playing between speaks.
    • Fixed a bug where HLS playlists would stop streaming after the initial playlist had been played to completion.
    • Fixed a bug where Audible playback could not advance to the next chapter.
    • Fixed some occurrences of SDK entering the IDLE state during the transition between Listening and Speaking states.
    • Fixed a bug where PlaybackFinished events were not reporting the correct offset.
      • An API change has been made to MediaPlayerInterface::getOffset(). This method is now required to return the final offset when called after playback has stopped.
    • Fixed a problem where AIP was erroneously resetting its state upon getting a cancelDirective() callback.

Version 1.2.1 - November 11 2017

  • Enhancements
    • Added comments to AlexaClientSDKConfig.json. These descriptions provide additional guidance for what is expected for each field.
    • Enabled pause and resume controls for Pandora.
  • Bug Fixes
    • Bug fix for issue #329 - HTTP2Transport instances no longer leak when SERVER_SIDE_DISCONNECT is encountered.
    • Bug fix for issue #189 - Fixed a race condition in the Timer class that sometimes caused SpeechSynthesizer to get stuck in the "Speaking" state.
    • Bug fix for a race condition that caused SpeechSynthesizer to ignore subsequent Speak directives.
    • Bug fix for corrupted mime attachments.

Version 1.2.0 - October 27 2017

  • Enhancements
    • Updated MediaPlayer to solve stability issues
    • All capability agents were refined to work with the updated MediaPlayer
    • Added the TemplateRuntime capability agent
    • Added the SpeakerManager capability agent
    • Added a configuration option ("sampleApp":"endpoint") that allows the endpoint that SampleApp connects to to be specified without changing code or rebuilding
    • Added very verbose capture of libcurl debug information
    • Added an observer interface to observer audio state changes from AudioPlayer
    • Added support for StreamMetadataExtracted Event. Stream tags found in the stream are represented in JSON and sent to AVS
    • Added to the SampleApp a simple GuiRenderer as an observer to the TemplateRuntime Capability Agent
    • Moved shared libcurl functionality to AVSCommon/Utils
    • Added a CMake option to exclude tests from the "make all" build. Use "cmake -DACSDK_EXCLUDE_TEST_FROM_ALL=ON" to enable it. When this option is enabled "make unit" and "make integration" still could be used to build and run the tests
  • Bug fixes:
    • Previously scheduled alerts now play following a restart
    • General stability fixes
    • Bug fix for CertifiedSender blocking forever if the network goes down while it's trying to send a message to AVS
    • Fixes for known issue of Alerts integration tests fail: AlertsTest.UserLongUnrelatedBargeInOnActiveTimer and AlertsTest.handleOneTimerWithVocalStop
    • Attempting to end a tap-to-talk interaction with the tap-to-talk button wouldn't work
    • SharedDataStream could encounter a race condition due to a combination of a blocking Reader and a Writer closing before writing any data
    • Bug-fix for the ordering of notifications within alerts scheduling. This fixes the issue where a local-stop on an alert would also stop a subsequent alert if it were to begin without delay

Version 1.1.0 - October 10 2017

  • Enhancements
    • Better GStreamer error reporting. MediaPlayer used to only report MEDIA_ERROR_UNKNOWN, now reports more specific errors as defined in ErrorType.h.
    • Codebase has been formatted for easier reading.
    • DirectiveRouter::removeDirectiveHandler() signature changed and now returns a bool indicating if given handler should be successfully removed or not.
    • Cleanup of raw and shared pointers in the creation of Transport objects.
    • HTTP2Streams now have IDs assigned as they are acquired as opposed to created, making associated logs easier to interpret.
    • AlertsCapabilityAgent has been refactored.
      • Alert management has been factored out into an AlertScheduler class.
    • Creation of Reminder (implements Alert) class.
    • Added new capability agent for PlaybackController with unit tests.
    • Added Settings interface with unit tests.
    • Return type of getOffsetInMilliseconds() changed from int64_t to std::chronology::milliseconds.
    • Added AudioPlayer unit tests.
    • Added teardown for all Integration tests except Alerts.
    • Implemented PlaylistParser.
  • Bug fixes:

Version 1.0.3 - September 19 2017

Version 1.0.2 - August 23 2017

  • Removed code from AIP which propagates ExpectSpeech initiator strings to subsequent Recognize events. This code will be re-introduced when AVS starts sending initiator strings.

Version 1.0.1 - August 08 2017

  • Added a fix to the sample app so that the StateSynchronization event is the first that gets sent to AVS.
  • Added a POST_CONNECTED enum to ConnectionStatusObserver.
  • StateSychronizer now automatically sends a StateSynchronization event when it receives a notification that ACL is CONNECTED.
  • Added make install for installing the AVS Device SDK.
  • Added an optional make networkIntegration for integration tests for slow network (only on Linux platforms).
  • Added shutdown management which fully cleans up SDK objects during teardown.
  • Fixed an issue with AudioPlayer barge-in which was preventing subsequent audio from playing.
  • Changed Mediaplayer buffering to reduce stuttering.
  • Known Issues:
    • Connection loss during some states keep the app in that state even after connection is regained. Pressing ‘s’ unsticks the state.
    • Play/Pause media restarts it from the beginning.
    • SpeechSynthesizer shows wrong UX state during a burst of Speaks.
    • Quitting the sample app while AudioPlayer is playing something causes a segmentation fault.
    • AudioPlayer sending PlaybackPaused during flash briefing.
    • Long Delay playing live stations on iHeartRadio.
    • Teardown warnings at the end of integration tests.

Version 1.0.0 - August 07 2017

  • Added AudioPlayer capability agent.
    • Supports iHeartRadio.
  • StateSynchronizer has been updated to better enforce that System.SynchronizeState is the first Event sent on a connection to AVS.
  • Additional tests have been added to ACL.
  • The Sample App has been updated with several small fixes and improvements.
  • ADSL was updated such that all directives are now blocked while the handling of previous SpeechSynthesizer.Speak directives complete. Because any directive may now be blocked, the preHandleDirective() / handleDirective() path is now used for handling all directives.
  • Fixes for the following GitHub issues:
  • A bug causing ACL to not send a ping to AVS every 5 minutes, leading to periodic server disconnects, was fixed.
  • Subtle race condition issues were addressed in the Executor class, resolving some intermittent crashes.
  • Known Issues
    • Native components for the following capability agents are not included in this release: PlaybackController, Speaker, Settings, TemplateRuntime, and Notifications.
    • MediaPlayer
      • Long periods of buffer underrun can cause an error related with seeking and subsequent stopped playback.
      • Long periods of buffer underrun can cause flip flopping between buffer_underrun and playing states.
      • Playlist parsing is not supported unless -DTOTEM_PLPARSER=ON is specified.
    • AudioPlayer
      • Amazon Music, TuneIn, and SiriusXM are not supported in this release.
      • Our parsing of urls currently depends upon GNOME/totem-pl-parser which only works on some Linux platforms.
    • AlertsCapabilityAgent
      • Satisfies the AVS specification except for sending retrospective Events. For example, sending AlertStarted Event for an Alert which rendered when there was no internet connection.
    • Sample App:
      • Any connection loss during some states keeps the app stuck in that state, unless the ongoing interaction is manually stopped by the user.
      • The user must wait several seconds after starting up the sample app before the sample app is properly usable.
    • Tests:
      • SpeechSynthesizer unit tests hang on some older versions of GCC due to a tear down issue in the test suite
      • Intermittent Alerts integration test failures caused by rigidness in expected behavior in the tests

Version 0.6.0 - July 14 2017

  • Added a sample app that leverages the SDK.
  • Added Alerts capability agent.
  • Added the DefaultClient class.
  • Added the following classes to support directives and events in the System interface: StateSynchronizer, EndpointHandler, and ExceptionEncounteredSender.
  • Added unit tests for ACL.
  • Updated MediaPlayer to play local files given an std::istream.
  • Changed build configuration from Debug to Release.
  • Removed DeprecatedLogger class.
  • Known Issues:
    • MediaPlayer: Our GStreamer based implementation of MediaPlayer is not fully robust, and may result in fatal runtime errors, under the following conditions:
      • Attempting to play multiple simultaneous audio streams
      • Calling MediaPlayer::play() and MediaPlayer::stop() when the MediaPlayer is already playing or stopped, respectively.
      • Other miscellaneous issues, which will be addressed in the near future
    • AlertsCapabilityAgent:
      • This component has been temporarily simplified to work around the known MediaPlayer issues mentioned above
      • Fully satisfies the AVS specification except for sending retrospective Events, for example, sending AlertStarted for an Alert which rendered when there was no Internet connection
      • This component is not fully thread-safe, however, this will be addressed shortly
      • Alerts currently run indefinitely until stopped manually by the user. This will be addressed shortly by having a timeout value for an alert to stop playing.
      • Alerts do not play in the background when Alexa is speaking, but will continue playing after Alexa stops speaking.
    • Sample App:
      • Without the refresh token being filled out in the JSON file, the sample app crashes on start up.
      • Any connection loss during some states keeps the app stuck in that state, unless the ongoing interaction is manually stopped by the user.
      • At the end of a shopping list with more than 5 items, the interaction in which Alexa asks the user if he/she would like to hear more does not finish properly.
    • Tests:
      • SpeechSynthesizer unit tests hang on some older versions of GCC due to a tear down issue in the test suite
      • Intermittent Alerts integration test failures caused by rigidness in expected behavior in the tests

Version 0.5.0 - June 23 2017

Version 0.4.1 - June 9 2017

Version 0.4.0 - May 31 2017 (patch)

  • Added AuthServer, an authorization server implementation used to retrieve refresh tokens from LWA.

Version 0.4.0 - May 24 2017

  • Added SpeechSynthesizer, an implementation of the SpeechRecognizer capability agent.
  • Implemented a reference MediaPlayer based on GStreamer for audio playback.
  • Added MediaPlayerInterface that allows you to implement your own media player.
  • Updated ACL to support asynchronous receipt of audio attachments from AVS.
  • Bug Fixes:
    • Some intermittent unit test failures were fixed.
  • Known Issues:
    • ACL's asynchronous receipt of audio attachments may manage resources poorly in scenarios where attachments are received but not consumed.
    • When an AttachmentReader does not deliver data for prolonged periods MediaPlayer may not resume playing the delayed audio.

Version 0.3.0 - May 17 2017

  • Added the CapabilityAgent base class that is used to build capability agent implementations.
  • Added ContextManager, a component that allows multiple capability agents to store and access state. These Events include Context, which is used to communicate the state of each capability agent to AVS in the following Events:
  • Added SharedDataStream (SDS) to asynchronously communicate data between a local reader and writer.
  • Added AudioInputProcessor (AIP), an implementation of a SpeechRecognizer capability agent.
  • Added WakeWord Detector (WWD), which recognizes keywords in audio streams. [0.3.0] implements a wrapper for KITT.ai.
  • Added a new implementation of AttachmentManager and associated classes for use with SDS.
  • Updated ACL to support asynchronously sending audio to AVS.

Version 0.2.1 - May 03 2017

  • Replaced the configuration file AuthDelegate.config with AlexaClientSDKConfig.json.
  • Added the ability to specify a CURLOPT_CAPATH value to be used when libcurl is used by ACL and AuthDelegate. See See Appendix C in the README for details.
  • Changes to ADSL interfaces:
    • The [0.2.0] interface for registering directive handlers (DirectiveSequencer::setDirectiveHandlers()) was problematic because it canceled the ongoing processing of directives and dropped further directives until it completed. The revised API makes the operation immediate without canceling or dropping any handling. However, it does create the possibility that DirectiveHandlerInterface methods preHandleDirective() and handleDirective() may be called on different handlers for the same directive.
    • DirectiveSequencerInterface::setDirectiveHandlers() was replaced by addDirectiveHandlers() and removeDirectiveHandlers().
    • DirectiveHandlerInterface::shutdown() was replaced with onDeregistered().
    • DirectiveHandlerInterface::preHandleDirective() now takes a std::unique_ptr instead of a std::shared_ptr to DirectiveHandlerResultInterface.
    • DirectiveHandlerInterface::handleDirective() now returns a bool indicating if the handler recognizes the messageId.
  • Bug fixes:
    • ACL and AuthDelegate now require TLSv1.2.
    • onDirective() now sends ExceptionEncountered for unhandled directives.
    • DirectiveSequencer::shutdown() no longer sends ExceptionEncountered() for queued directives.

Version 0.2.0 - March 27 2017 (patch)

  • Added memory profiling for ACL and ADSL. See Appendix A in the README.
  • Added a command to build the API documentation.

Version 0.2.0 - March 99 2017

  • Added Alexa Directive Sequencer Library (ADSL) and Alexa Focus Manager Library (AMFL).
  • CMake build types and options have been updated.
  • Documentation for libcurl optimization included.

Version 0.1.0 - February 10 2017

  • Initial release of the Alexa Communications Library (ACL), a component which manages network connectivity with AVS, and AuthDelegate, a component which handles user authorization with AVS.