Release Notes

Version: Legato 19.11.6
Date: December 10th, 2021
Legato Application Framework Licensing Information

Visit the release page to download the tarball, clone the repositories from GitHub, or view previous released versions.

Get started with the 19.11.6 version of Legato by installing the SDK through Leaf.

Search for the 19.11.6 version for your target (using wp76xx as an example):

$ leaf search 19.11.6 -t wp76xx
leaf setup <profile name> -p <package identifier>


leaf search 19.11.6 -t wp77xx
leaf setup <profile name> -p <package identifier>
The 19.11 release branch is the long term supported version for Sierra Wireless modules. Future Sierra Wireless module releases will be using the 19.11 release. The 19.11 branch is the last version that will support the Linux 3.18/3.14 kernel.

19.11.6 Patch

The 19.11.6 patch introduces:

  • a bug fix for a watchdog error during a FOTA operation
  • a bug fix for generating binary app packages
  • a bug fix for file recovery when R/W partition is corrupted
  • support for new image types
  • improve connection service in poor network conditions
  • disable APN switch

19.11.5 Patch

The 19.11.5 patch introduces:

  • a bug fix for a memory leak in avcDaemon
  • a bug fix for potentially unwanted device behaviour because of a SFS file handler leak
  • a bug fix removing an extra forward slash in GPIO pins

19.11.4 Patch

The 19.11.4 patch introduces:

  • removing the connection test included in the "cm data connect" command execution.
  • the transition from Gerrit to Github for future releases.

19.11.3 Patch

The 19.11.3 patch introduces:

  • reduced logging for the AirVantage client to clean up redundant messaging.
  • a bug fix to allow over 176 bytes to be recieved by the SMS service.
  • support for NTP through AirVantage.

19.11.1 Patch

The 19.11.1 patch introduces:

  • clarification for MPL V2 licensing in Linux Scripts.
  • provides updated documentation and information on the Legato plugin for VSCode Version 1.0.
  • fixed an issue where the AirVantage server is not notified that a reboot is pending on the target.

New Features

List of new features in the 19.11.3 Patch:

Ultra Low Power Mode

An API function, le_ulpm_SetShutDownStrategy() has been modified to configure low power mode before shutting down the module.

List of new features in the 19.11.1 Patch:

Ultra Low Power Mode Reboot

A new API function, le_ulpm_Reboot() has been added to initiate the reboot of the processor and modem.

List of new features in the 19.11 Release:

Enable secStore Admin

In order to enable the secure storage admin API, Legato must be compiled using the SECSTOREADMIN flag.

make distclean
SECSTOREADMIN=1 make wp76xx

Alternatively, you can enable the Secure Storage Admin API from within the kconfig menu system.

make menuconfig_wp76xx

In the displayed configuration menu, enable SecStore Admin API flag by following the following menu path and enabling Enable Secure Storage Administration API Services > Secure Storage > Enable Secure Storage Administration API

LTE Band Support

New support has been added for band 66 and 71, see Modem Radio Control for more details.

dcs GetChannels

le_dcs_GetChannels() now returns a channel's admin state than then operational state.

Multiple DNS Configuration

le_net Interface now supports having multiple versions of DNS configuration.

APN name deprecation

The DCS functionality to populate the default APN name into the cellular channel's modem profile if blank at startup upon an attempt to start is now removed from both le_dcs Interface and Data Connection.

Timezone File Set

le_clk_SetTimezoneFile is now supported in System Clock API .

tty Open change

Previous versions of le_tty_Open() would exit the process with LE_FATAL if the tty failed to successfully open; now a file descriptor is either returned or -1 is returned on failure.

Beta Features

Experimental IDE

The Legato team has launched the beta version of a Legato Plugin for VSCode.

Alpha Features

The following are the list of features that have been added into the 19.11 Release but are still being developed and should not be used on production targets. Please provide feedback for these features on our forums:

Legato RPC

RPC has been added as an experimental feature (Remote-procedure Call Remote procedure call). Please refer to getStartRPC Legato RPC on how to get started.

Fixed Issues

All changes are tagged in GitHub as "19.11.0". The full list of changes and commit messages can be found on GitHub.

This is only the list of fixes for the Application Framework and Platform Services, for the list of changes in the Platform Adapter view the commits under the tag 19.11.0 in individual repositories on GitHub.

Known Issues

Constraints and Limitations

Dev Machine Linux Version

To develop applications within the Legato Application Framework, a current supported Long Term Support version of Ubuntu Linux is required on your dev machine (or running in a virtual box on Windows). Ubuntu 18.04 is the current recommended version to use on your dev machine.

ECM-USB modem manager issue

Ubuntu 15.10 and newer has Modem Manager version 1.4.12-1ubuntu1 installed by default which conflicts with the ECM-USB driver when connecting a target. Modem manager may cause the Ubuntu Network Manager to crash on your host and/or your target device to become unavailable over USB.


  • NetworkManager crashing when plugging into your device over USB, or
  • The target device becomes inaccessible after 30 seconds.

Recommended Work Around:

FOTA upgrade warning

A device that has trustzones enabled, may re-bootstrap (obtain new keys from the AirVantage server) durring a FOTA (firmware over-the-air) upgrade.