This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Zephyr Kernel 1.8.0

We are pleased to announce the release of Zephyr kernel version 1.8.0.

Major enhancements with this release include:

  • Tickless kernel

  • IP Stack improvements

  • Bluetooth 5.0 features

  • Ecosystem: Tracing, debugging support through third-party tools (openocd, Segger Systemview)

  • Improved build support on Mac and Windows development environments

  • Xtensa GCC support

  • Initial implementation of MMU/MPU support

  • Expanded device support

The following sections provide detailed lists of changes by component.


  • Use k_cycle_get_32 instead of sys_cycle_get_32 for Kernel

  • Added k_panic() and k_oops() APIs for Kernel

  • Added k_thread_create() API for Kernel

  • Added k_queue API for Kernel

  • Add tickless kernel support


  • arm: Update core to use struct k_thread

  • arm: Added ARM MPU support

  • dts: Added ARM CMSDK support

  • arm: Added Initial support for NXP MPU

  • arm: Added Device Tree Support for nRF52832 SoC based boards

  • arm: Fixed nRF52840-QIAA SoC support for device tree

  • arm: Added Device Tree Support for nRF52840 SoC & boards

  • arm: Added Device Tree Support for nRF51822 SoC & boards

  • dts: Introduced st/mem.h for FLASH & SRAM sizes

  • dts: Put IRQ priority into the interrupt property

  • arm: Support for MKL25Z soc

  • arm: Added FPU support

  • x86: defined MMU data structures

  • Support for ARC EM Starter Kit version 2.3 added


  • Added qemu_xtensa board definition

  • Added a more informative page fault handler x86 board

  • xtensa: build similar to other Zephyr arches

  • Define MMU data structures for x86 board

  • Added support for board disco_l475_iot1

  • Added STM32F413 Nucleo board

  • Added support for the CC3220SF_LAUNCHXL board

  • Support for new ARM board FRDM-KL25Z

  • arduino_101 board enable GPIO by default

  • boards: convert to using newly introduced integer sized types

  • arm: Added support for Nucleo L432KC board

  • arm: Added support for STM32L496G Discovery board

  • arm: Added support for STM32F469I-DISCO board

  • BBC micro:bit: Added driver & API for the 5x5 LED display

Drivers and Sensors

  • UART interrupt-driver API is better defined

  • Support for pull-style console API

  • nRF5 IEEE 802.15.4 radio driver added

  • KW41Z IEEE 802.15.4 radio driver added

  • Added MCUX TRNG driver

  • Added support for the SiFive Freedom E310 pinmux driver

  • drivers/sensor: Convert formatter strings to use PRI defines

  • Added lps22hb sensor driver

  • Added lsm6dsl sensor driver

  • Added heart rate sensor driver

  • Added support for max30101 heart rate sensor

  • Added support for lis2dh accelerometer


  • HTTPS server support added

  • HTTP Basic-Auth support added

  • IPv6 fragmentation support added

  • Add block wise support to CoAP for well-known response

  • Big refactoring of network buffer handling

  • Start to collect TCP statistics if enabled in config

  • IEEE 802.15.4 security support added

  • DNS resolver sample application added

  • IPv6 multicast listener (MLDv2) support added

  • NATS protocol sample application added

  • HTTP client and server connectivity fixes

  • Network samples Coverity fixes

  • Network samples llvm compiler warning fixes

  • MQTT publisher connectivity fixes

  • 6lo IPv6 header compression fixes

  • CoAP connectivity fixes

  • DHCPv4 connectivity fixes

  • TCP connectivity fixes

  • DNS documentation and connectivity fixes

  • IPv6 connectivity fixes

  • IPv4 ARP fixes

  • IEEE 802.15.4 configuration tweaking fixes

  • Remove ORFD (Overly Reduced Function Device) 802.15.4 support

  • Network offloading driver fixes

  • Fix various memory leaks

  • Properly check TCP and UDP checksum before accepting packet

  • Start RX and TX network threads in proper order

  • Network samples documentation fixes and clarifications

  • RPL mesh routing fixes

  • Network link (MAC) address fixes


  • Host: Added ATT and SMP packet tracking for flow control enforcement

  • Host: GATT database changed to a linked list in preparation for dynamic allocation

  • Bluetooth 5.0: The Controller reports itself as 5.0-capable

  • Bluetooth 5.0: Introduced Channel Selection Algorithm #2 support

  • Bluetooth 5.0: Added Multiple PHY support, both 2Mbit/s and long-range coded

  • Bluetooth 5.0: Integrated Scan Request notifications

  • Controller: Added Low Duty Cycle Directed Advertising support

  • Controller: Added Scan duplicate filtering support

  • Controller: Enforced complete role separation in the controller for smaller builds

  • Controller: Introduced Advanced Controller configuration with several new Kconfig options

  • Controller: Changed the radio interrupts to direct ISRs to reduce interrupt latency

  • Added HCI Controller to Host flow control support in both Host and Controller

  • BR/EDR: Added HFP (e)SCO audio channel establishment support

  • BR/EDR: Added support for a functional SDP server

Build and Infrastructure

  • Support building host tools

  • Added separate DTS target

  • Added support for MSYS2

  • Use -O2 instead of -Os for ARC with SDK 0.9


  • Added library for software driven I2C

  • Created a HTTP library

  • Added HTTP server library support

  • Added minimal JSON library

  • Update TinyCrypt to version 0.2.6

  • Added minimal JSON library


  • Added Atmel SAM family I2C (TWIHS) driver

  • Added Atmel SAM serial (UART) driver

  • Added WDT driver for Atmel SAM SoCs

  • Added Atmel SAM4S SoC support

  • Imported Nordic 802.15.4 radio driver

  • Added Initial support for NXP MPU

  • Updated QMSI to 1.4 RC4

  • Added FPU support

  • Added basic support for STM32F413

  • Introduced STM32F4x DMA driver

  • pinmux: stm32: Added support for Nucleo L432KC

  • Added support for STM32L496G Discovery board

  • Added dts for STM32F407

  • Added support for STM32F4DISCOVERY Board

  • Added support for STM32F469XI

  • Added support for STM32F469I-DISCO


  • Board documentation added for new board ports

  • Added a board porting guide

  • Added security sections to porting and user guides

  • Continued migration of material to website and github wiki

  • Improved CSS formatting and appearance of generated documents

  • Added breadcrumb navigation header with kernel version number

  • Updated getting started setup guides for Linux, Windows, and macOS

  • Updates and additions to follow new and updated kernel features

  • Broken link and spelling check scans

  • Removed deprecated kernel documentation (pre 1.6 release) from website (still available in git repo if needed)

Tests and Samples

  • Added test to verify same tick timeout expiry order

  • Added clock_test for kernel

  • Added tickless tests

  • Added a simple CC2520 crypto dev test

  • Added combined observer & broadcaster app for Bluetooth samples

  • Added support to wait both IPv4 and IPv6

  • Enabled tickless kernel option in some apps