nRF Connect SDK v1.2.1 Release Notes

nRF Connect SDK delivers reference software and supporting libraries for developing low-power wireless applications with Nordic Semiconductor products. It includes the MCUboot and the Zephyr RTOS open source projects, which are continuously integrated and re-distributed with the SDK.

nRF Connect SDK v1.2.1 supports product development with the nRF9160 Cellular IoT device. It contains reference applications, sample source code, and libraries for developing low-power wireless applications with nRF52 and nRF53 Series devices, though support for these devices is incomplete and not recommended for production.


Before this release, the nRF Connect SDK moved to a new GitHub organization, nrfconnect. All repositories were renamed to provide clear and concise names that better reflect the composition of the codebase. If you are a new nRF Connect SDK user, there are no actions you need to take. If you used previous releases of the nRF Connect SDK, you should point your repositories to the right remotes.


  • Updates to LwM2M carrier library

  • Updates to BSD library

Release tag

The release tag for the nRF Connect SDK manifest repository ( is v1.2.1. Check the west.yml file for the corresponding tags in the project repositories.

To use this release, check out the tag in the manifest repository and run west update. See Get the nRF Connect SDK code for more information.

Supported modem firmware

This version of the nRF Connect SDK supports the following modem firmware for cellular IoT applications:

  • mfw_nrf9160_1.1.2

Use the nRF Programmer app of nRF Connect for Desktop to update the modem firmware. See Updating the modem firmware for instructions.

Tested boards

The following boards have been used during testing of this release:

  • PCA10090 (nRF9160 DK)

  • PCA20035 (Thingy:91)

  • PCA10095 (nRF5340 PDK)

  • PCA10056 (nRF52840 DK)

  • PCA10059 (nRF52840 Dongle)

  • PCA10040 (nRF52 DK)

For the full list of supported devices and boards, see Supported Boards in the Zephyr documentation.

Required tools

In addition to the tools mentioned in Installing manually, the following tool versions are required to work with the nRF Connect SDK:



Download link



J-Link Software and Documentation Pack

nRF Command Line Tools


nRF Command Line Tools

nRF Connect for Desktop

v3.3.0 or later

nRF Connect for Desktop

dtc (Linux only)

v1.4.6 or later

Install the required tools


See Install the GNU Arm Embedded Toolchain

GNU Arm Embedded Toolchain

As IDE, we recommend to use SEGGER Embedded Studio (Nordic Edition) version 4.52. It is available from the following platforms:

  • Windows x86

  • Windows x64

  • Mac OS x64

  • Linux x86

  • Linux x64


The following sections provide detailed lists of changes by component.


  • Download client:

    • Fixed DNS lookup when using non-default PDN.

  • LwM2M carrier:

    • Updated to version 0.8.2. See the Changelog for detailed information.

  • BSD library:

    • Updated to version See the Changelog for detailed information.