Zephyr 3.3.0

We are pleased to announce the release of Zephyr version 3.3.0.

Major enhancements with this release include:

  • Introduced Fuel Gauge subsystem for battery level monitoring.

  • Introduced USB-C device stack with PD (power delivery) support.

  • Introduced DSP (digital signal processing) subsystem with CMSIS-DSP as the default backend.

  • Added Picolibc support for all architectures when using Zephyr SDK.

The following sections provide detailed lists of changes by component.

API Changes

  • Emulator creation APIs have changed to better match DEVICE_DT_DEFINE. It also includes a new backend API pointer to allow sensors to share common APIs for more generic tests.

Changes in this release

  • Newlib nano variant is no longer selected by default when CONFIG_NEWLIB_LIBC is selected. CONFIG_NEWLIB_LIBC_NANO must now be explicitly selected in order to use the nano variant.

  • Bluetooth: Added extra options to bt_le_per_adv_sync_transfer_subscribe to allow disabling sync reports, and enable sync report filtering. these two options are mutually exclusive.

  • Bluetooth: CONFIG_BT_PER_ADV_SYNC_TRANSFER_RECEIVER and CONFIG_BT_PER_ADV_SYNC_TRANSFER_SENDER have been added to enable the PAST implementation rather than CONFIG_BT_CONN.


  • Regulator APIs previously located in <zephyr/drivers/regulator/consumer.h> are now part of <zephyr/drivers/regulator.h>.

  • Starting from this release zephyr- prefixed tags won’t be created anymore. The project will continue using v tags, for example v3.3.0.

  • Bluetooth: Deprecated the Bluetooth logging subsystem in favor of the Zephyr standard logging system. To enable debugging for a particular module in the Bluetooth subsystem, enable CONFIG_BT_(module name)_LOG_LEVEL_DBG instead of CONFIG_BT_DEBUG_(module name).

  • MCUmgr img_mgmt now requires that a full sha256 hash to be used when uploading an image to keep track of the progress, where the sha256 hash is of the whole file being uploaded (different to the hash used when getting image states). Use of a truncated hash or non-sha256 hash will still work but will cause issues and failures in client software with future updates to Zephyr/MCUmgr such as image verification.

  • MCUmgr handlers no longer need to be registered by the application code, handlers just need to use a define which will then call the supplied registration function at boot-up. If applications register this then those registrations should be removed to prevent registering the same handler multiple times.

  • MCUmgr Bluetooth and UDP transports no longer need to be registered by the application code, these will now automatically be registered at boot-up (this feature can be disabled for the UDP transport by setting CONFIG_MCUMGR_TRANSPORT_UDP_AUTOMATIC_INIT). If applications register transports then those registrations should be removed to prevent registering the same transport multiple times.

  • MCUmgr transport Kconfigs have changed from select to depends on which means that for applications using the Bluetooth transport, applications will now need to enable the following:

    For CDC or serial transports:

    For shell transport:

    For UDP transport:

  • MCUmgr fs_mgmt hash/checksum function, type and variable names have been changed to be prefixed with fs_mgmt_ to retain alignment with other zephyr and MCUmgr APIs.

  • Python’s argparse argument parser usage in Zephyr scripts has been updated to disable abbreviations, any future python scripts or python code updates must also disable allowing abbreviations by using allow_abbrev=False when setting up ArgumentParser().

    This may cause out-of-tree scripts or commands to fail if they have relied upon their behaviour previously, these will need to be updated in order for building to work. As an example, if a script argument had --reset-type and an out-of-tree script used this by passing --reset then it will need to be updated to use the full argument name, --reset-type.

  • Rewrote the CAN API to utilize flag bitfields instead discrete of struct members for indicating standard/extended CAN ID, Remote Transmission Request (RTR), and added support for filtering of CAN-FD format frames.

  • New Zephyr message bus (Zbus) subsystem added; a message-oriented bus that enables one-to-one, one-to-many and many-to-many communication between threads.

  • zTest now supports controlling test summary printouts via the CONFIG_ZTEST_SUMMARY. This Kconfig can be set to n for less verbose test output.

  • Emulators now support a backend API pointer which allows a single class of devices to provide similar emulated functionality. This can be used to write a single test for the class of devices and testing various boards using different chips.

Removed APIs in this release

  • Removed CONFIG_COUNTER_RTC_STM32_LSE_DRIVE* This should now be configured using the driving_capability property of LSE clock

  • Removed CONFIG_COUNTER_RTC_STM32_LSE_BYPASS This should now be configured using the new lse_bypass property of LSE clock

  • Removed CONFIG_COUNTER_RTC_STM32_BACKUP_DOMAIN_RESET. Its purpose was to control the reset of the counter value at board reset. It is removed since it has too wide scope (full Backup RAM reset). Replaced by CONFIG_COUNTER_RTC_STM32_SAVE_VALUE_BETWEEN_RESETS which also allows to control the reset of counter value, with an opposite logic.

  • Removed deprecated tinycbor module, code that uses this module should be updated to use zcbor as a replacement.

  • Removed deprecated GPIO flags used for setting debounce, drive strength and voltage level. All drivers now use vendor-specific flags as needed.

  • Removed deprecated UTIL_LISTIFY helper macro.

  • Removed deprecated pwm_pin* family of functions from the PWM API.

  • Removed deprecated nvs_init function from the NVS filesystem API.

  • Removed deprecated DT_CHOSEN_*_LABEL helper macros.

  • Removed deprecated property enable-pin-remap from :dtcompatible: st,stm32-usb:. remap-pa11-pa12 from :dtcompatible: st-stm32-pinctrl: should now be used.

Deprecated in this release

Stable API changes in this release

  • MCUmgr events have been reworked to use a single, unified callback system. This allows better customisation of the callbacks with a lower flash size. Applications using the existing callback system will need to be upgraded to use the new API by following the migration guide

  • net_pkt_get_frag(), net_pkt_get_reserve_tx_data() and net_pkt_get_reserve_rx_data() functions are now requiring to specify the minimum fragment length to allocate, so that they work correctly also in case CONFIG_NET_BUF_VARIABLE_DATA_SIZE is enabled. Applications using this APIs will need to be updated to provide the expected fragment length.

  • Marked the Controller Area Network (CAN) controller driver API as stable.

New APIs in this release


  • Added an “EARLY” init level that runs immediately on entry to z_cstart()

  • Refactored the internal CPU count API to allow for runtime changes

  • Added support for defining application main() in C++ code

  • Fixed a race condition on SMP when pending threads where a second CPU could attempt to run a thread before the pending thread had finished the context switch.


  • ARC

    • Fixed & reworked interrupt management (enabling / disabling) for the SMP systems

    • Added TLS (thread-local storage) for ARC MWDT toolchain

    • Fixed & rework irq_offload implementation

    • Fixed multiple logging & cbprintf issues for ARCv3 64bit

    • Added XIP support with MWDT toolchain

    • Improved DSP support, add DSP and AGU context save / restore

    • Added XY memory support for ARC DSP targets

    • Added architectures-specific DSP tests

    • Added additional compile-time checks for unsupported configuration: ARC_FIRQ + ARC_HAS_SECURE

    • Added support for using __auto_type type for ARC MWDT toolchain

    • Added support for using _Generic and __fallthrough keywords for ARC MWDT toolchain

    • Bumped minimal required ARC MWDT version to 2022.09

    • Fixed & reworked inclusion of C/C++ headers for ARC MWDT toolchain which cased build issue with C++

  • ARM

    • More precise ‘reason’ codes are now returned in the fault handler.

    • Cache functions now use proper sys_* functions.

    • Renamed default RAM region from SRAM to RAM.

  • ARM64

    • Implemented ASID support for ARM64 MMU

  • RISC-V


    • Added support for hardware register stacking/unstacking during ISRs and exceptions.

    • Added support for overriding arch_irq_lock(), arch_irq_unlock() and arch_irq_unlocked().

    • Zephyr CPU number is now decoupled from the hart ID.

    • Secondary boot code is no longer included when CONFIG_MP_MAX_NUM_CPUS equals 1.

    • IPIs are no longer hardcoded to z_sched_ipi().

    • Implemented an on-demand context switching algorithm for thread FPU accesses.

    • Enabled booting from non-zero indexed RISC-V harts with CONFIG_RV_BOOT_HART.

    • Hart IDs are now mapped to Zephyr CPUs with the devicetree.

    • Added a workaround for MTVAL not updating properly on QEMU-based platforms.


  • Audio

    • Refactored the handling of extended and periodic advertising in the BAP broadcast source.

    • Implemented the Common Audio Profile initiator role.

    • Added support for Broadcast source subgroup and BIS codec configuration.

    • Renamed the CSI and VCP functionality to use the “P” postfix for profile instead of “S” for service.

    • Added a broadcast source metadata update function.

    • Added (un)binding of audio ISO structs to Audio Streams.

    • Added support for encrypted broadcast.

    • Added the ability to change the supported contexts in PACS.

    • Improved stream coupling for CIS as the unicast client

    • Added broadcast source metadata update function

    • Added packing to unicast group create

    • Added packing field to broadcast source

    • Renamed BASS and BASS client to BAP Scan Delegator and BPA Broadcast Assistant

    • Added support for multiple subgroups for BAP broadcast sink

    • Replaced capabilities API with PACS

  • Host

    • Added a new BT_CONN_INTERVAL_TO_US utility macro.

    • Made the HCI fragmentation logic asynchronous, thus fixing a long-standing potential deadlock between data and control procedures.

    • Added the local advertising address to bt_le_ext_adv_get_info().

    • Improved the implementation of bt_disable() to handle additional edge cases.

    • Removed all Bluetooth-specific logging macros and functionality, switching instead to the OS-wide ones.

    • Added a new bt_le_per_adv_sync_lookup_index() function.

    • Fixed missing calls to bt_le_per_adv_sync_cb.term when deleting a periodic advertising sync object.

    • Added local advertising address to bt_le_ext_adv_info.

    • Added the printing of function names by default when logging.

    • Changed the policy for advertising restart after disconnection, which is now done only for connections in the peripheral role.

    • Added a guard to prevent bonding to the same device more than once.

    • Refactored crypto functionality from SMP into its own folder, and added the h8 crypto function.

    • Changed the behavior when receiving an L2CAP K-frame larger than the MPS, disconnecting instead of truncating it.

    • Added a new BT_ID_ALLOW_UNAUTH_OVERWRITE that allows unauthorized bond overrides with multiple identities.

    • Added support for the object calculate checksum feature in OTS.

    • Changed back the semantics of BT_PRIVACY to refer to local RPA address generation.

    • Modified the SMP behavior when outside a pairing procedure. The stack no longer sends unnecessary Pairing Failed PDUs in that state.

    • ISO: Changed ISO seq_num to 16-bit

  • Mesh

    • Changed the default advertiser to be extended advertiser.

    • Made the provisioning feature set dynamic.

    • Made the maximum number of simultaneous Bluetooth connections that the mesh stack can use configurable via BT_MESH_MAX_CONN.

    • Changed the advertising duration calculation to avoid imprecise estimations.

    • Added the BT_MESH_FRIEND_ADV_LATENCY Kconfig option.

  • Controller

    • Implemented the Read/Write Connection Accept Timeout HCI commands.

    • Implemented the Sleep Clock Accuracy Update procedure.

    • Implemented additional ISO-related HCI commands.

    • Implemented ISO-AL SDU buffering and PDU release timeout.

    • Added support for handling fragmented AD without chaining PDUs.

    • Added support for multiple memory pools for advertising PDUs

    • Added support for retrying the automatic peripheral connection parameter update.

    • Added support for deferring anchor points moves using an external hook.

    • Added a new LL_ASSERT_MSG macro for verbose assertions.

    • Added long control PDU support.

    • Added support for Broadcast ISO encryption.

    • Added support for central CIS/CIG, including ULL and Nordic LLL.

    • Added support for peripheral CIS/CIG in the Nordic LLL.

    • Added the BT_CTLR_SLOT_RESERVATION_UPDATE Kconfig option.

    • Integrated ISOAL for ISO broadcast.

Boards & SoC Support

  • Added support for these SoC series:

    • Atmel SAMC20, SAMC21

    • Atmel SAME70Q19

    • GigaDevice GD32L23X

    • GigaDevice GD32A50X

    • NXP S32Z2/E2

  • Made these changes in other SoC series:

    • STM32F1: USB Prescaler configuration is now expected to be done using :dtcompatible: st,stm32f1-pll-clock: usbpre or :dtcompatible: st,stm32f105-pll-clock: otgfspre properties.

    • STM32F7/L4: Now supports configuring MCO.

    • STM32G0: Now supports FDCAN

    • STM32G4: Now supports power management (STOP0 and STOP1 low power modes).

    • STM32H7: Now supports PLL2, USB OTG HS and ULPI PHY.

    • STM32L5: Now supports RTC based Counter.

    • STM32U5: Now supports Crypto APIs through AES device.

    • STM32F7/L4: Now supports configuring MCO.

  • Changes for ARC boards:

    • Multiple fixes to mdb-hw and mdb-nsim west runners to improve usability

    • Added nsim_em11d board with DSP features (XY DSP with AGU and XY memory)

    • Fixed cy8c95xx I2C GPIO port init on HSDK board

    • Added SPI flash support on EM starter kit board

    • Multiple fixes for nSIM platform - configuration: adding of missing HW features or configurations sync

    • Improved creg_gpio platform driver - add pin_configure API

    • Added separate QEMU config qemu_arc_hs_xip for XIP testing

    • Added nsim_hs_sram, nsim_hs_flash_xip nSIM platforms to verify various memory models

    • nSIM board documentation overhaul

  • Added support for these ARM boards:

    • Adafruit ItsyBitsy nRF52840 Express

    • Adafruit KB2040

    • Atmel atsamc21n_xpro

    • GigaDevice GD32L233R-EVAL

    • GigaDevice GD32A503V-EVAL

    • nRF5340 Audio DK

    • Sparkfun pro micro RP2040

    • Arduino Portenta H7

    • SECO JUNO SBC-D23 (STM32F302)

    • ST Nucleo G070RB

    • ST Nucleo L4A6ZG

    • NXP X-S32Z27X-DC (DC2)

  • Added support for these ARM64 boards:

    • i.MX93 (Cortex-A) EVK board

    • Khadas Edge-V board

    • QEMU Virt KVM

  • Added support for these X86 boards:

    • Intel Raptor Lake CRB

  • Added support for these RISC-V boards:

    • Added LCD support for longan_nano board.

  • Made these changes in ARM boards:

    • sam4s_xplained: Enabled PWM

    • sam_e70_xplained: Added DMA devicetree entries for SPI

    • sam_v71_xult: Added DMA devicetree entries for SPI

    • tdk_robokit1: Added DMA devicetree entries for SPI

    • The scratch partition has been removed for the following Nordic boards and flash used by this area re-assigned to other partitions to free up space and rely upon the swap-using-move algorithm in MCUboot (which does not suffer from the same faults or stuck image issues as swap-using-scratch does): nrf21540dk_nrf52840 nrf51dk_nrf51422 nrf51dongle_nrf51422 nrf52833dk_nrf52833 nrf52840dk_nrf52811 nrf52840dk_nrf52840 nrf52840dongle_nrf52840 nrf52dk_nrf52805 nrf52dk_nrf52810 nrf52dk_nrf52832 nrf5340dk_nrf5340 nrf9160dk_nrf52840 nrf9160dk_nrf9160

      Note that MCUboot and MCUboot image updates from pre-Zephyr 3.3 might be incompatible with Zephyr 3.3 onwards and vice versa.

    • The default console for the nrf52840dongle_nrf52840 board has been changed from physical UART (which is not connected to anything on the board) to use USB CDC instead.

    • Forced configuration of FPU was removed from following boards: stm32373c_eval stm32f3_disco

    • On STM32 boards, configuration of USB, SDMMC and entropy devices that generally expect a 48MHz clock is now done using device tree. When available, HSI48 is enabled and configured as domain clock for these devices, otherwise PLL_Q output or MSI is used. On some boards, previous PLL SAI configuration has been changed to above options, since PLL SAI cannot yet be configured using device tree.

  • Made these changes in other boards:

    • The nrf52_bsim (natively simulated nRF52 device with BabbleSim) now models a nRF52833 instead of a nRF52832 device

  • Added support for these following shields:

    • Adafruit PCA9685

    • nPM6001 EK

    • nPM1100 EK

    • Semtech SX1262MB2DAS

    • Sparkfun MAX3421E

Build system and infrastructure

  • Code relocation

    • zephyr_code_relocate API has changed to accept a list of files to relocate and a location to place the files.

  • Sysbuild

    • Issue with duplicate sysbuild image name causing an infinite cmake loop has been fixed.

    • Issue with board revision not being passed to sysbuild images has been fixed.

    • Application specific configurations of sysbuild controlled images.

  • Userspace

    • Userspace option to disable using the relax linker option has been added.

  • Tools

    • Static code analyser (SCA) tool support has been added.

Drivers and Sensors

  • ADC

    • STM32: Now Supports sequencing multiple channels into a single read.

    • Fixed a problem in ADC_CHANNEL_CFG_DT that forced users to add artificial input-positive property in nodes related to ADC drivers that do not use configurable analog inputs when such drivers were used together with an ADC driver that uses such input configuration.

    • Added driver for TI CC13xx/CC26xx family.

    • Added driver for Infineon XMC4xxx family.

    • Added driver for ESP32 SoCs.

  • Battery-backed RAM

    • STM32: Added driver to enable support for backup registers from RTC.

  • CAN

    • Added RX overflow counter statistics support (STM32 bxCAN, Renesas R-Car, and NXP FlexCAN).

    • Added support for TWAI on ESP32-C3.

    • Added support for multiple MCP2515 driver instances.

    • Added Kvaser PCIcan driver and support for using it under QEMU.

    • Made the fake CAN test driver generally available.

    • Added support for compiling the Native Posix Linux CAN driver against Linux kernel headers prior to v5.14.

    • Removed the CONFIG_CAN_HAS_RX_TIMESTAMP and CONFIG_CAN_HAS_CANFD Kconfig helper symbols.

  • Clock control

    • STM32: HSI48 can now be configured using device tree.

  • Counter

    • STM32 RTC based counter domain clock (LSE/SLI) should now be configured using device tree.

    • Added Timer based driver for GigaDevice GD32 SoCs.

    • Added NXP S32 System Timer Module driver.

  • DAC

    • Added support for GigaDevice GD32 SoCs.

    • Added support for Espressif ESP32 SoCs.

  • DFU

  • Disk

    • STM32 SD host controller clocks are now configured via devicetree.

    • Zephyr flash disks are now configured using the zephyr,flash-disk devicetree binding

    • Flash disks can be marked as read only by setting the read-only property on the linked flash device partition.

  • DMA

    • Adjusted incorrect dma1 clock source for GD32 gd32vf103 SoC.

    • Atmel SAM: Added support to select fixed or increment address mode when using peripherals to memory or memory to peripheral transfers.

    • STM32 DMA variable scope cleanups

    • Intel GPDMA linked list transfer descriptors appropriately aligned to 64 byte addresses

    • Intel GPDMA fixed bug in transfer configuration to initialize cfg_hi and cfg_lo

    • STM32 DMA Support for the STM32MP1 series

    • SAM XDMAC fixes to enable usage with SPI DMA transfers

    • Intel GPDMA fixed to return errors on dma stop

    • Intel GPDMA disabled interrupts when unneeded

    • Intel GPDMA fixed for register/ip ownership

    • STM32U5 GPDMA bug fix for busy flag

    • STM32U5 Suspend and resume features added

    • Intel GPDMA Report total bytes read/written (linear link position) in dma status

    • DMA API get attribute function added, added attributes for scatter/gather blocks available to Intel HDA and Intel GPDMA drivers.

    • Intel GPDMA Power management functionality added

    • Intel HDA Power management functionality added

    • GD32 Slot used for peripheral selection

    • GD32 memory to memory support added

    • ESP32C3 GDMA driver added

    • Intel HDA underrun/overrun (xrun) handling and reporting added

    • Intel GPDMA underrun/overrun (xrun) handling nad reporting added

    • DMA API start/stop are defined to be repeatable callable with test cases added. STM32 DMA, Intel HDA, and Intel GPDMA all comply with the contract after patches.

    • NXP EDMA Unused mutex removed


    • Added fake EEPROM driver for testing purposes.

  • Ethernet

    • STM32: Default Mac address configuration is now uid based. Optionally, user can configure it to be random or provide its own address using device tree.

    • STM32: Added support for STM32Cube HAL Ethernet API V2 on F4/F7/H7. By default disabled, it can be enabled with CONFIG_ETH_STM32_HAL_API_V2.

    • STM32: Added ethernet support on STM32F107 devices.

    • STM32: Now supports multicast hash filtering in the MAC. It can be enabled using CONFIG_ETH_STM32_MULTICAST_FILTER.

    • STM32: Now supports statistics logging through CONFIG_NET_STATISTICS_ETHERNET. Requires use of HAL Ethernet API V2.

  • Flash

    • Flash: Moved CONFIG_FLASH_FLEXSPI_XIP into the SOC level due to the flexspi clock initialization occurring in the SOC level.

    • NRF: Added CONFIG_SOC_FLASH_NRF_TIMEOUT_MULTIPLIER to allow tweaking the timeout of flash operations.

    • spi_nor: Added property mxicy,mx25r-power-mode to jedec,spi-nor binding for controlling low power/high performance mode on Macronix MX25R* Ultra Low Power flash devices.

    • spi_nor: Added check if the flash is busy during init. This used to cause the flash device to be unavailable until the system was restarted. The fix waits for the flash to become ready before continuing. In cases where a full flash erase was started before a restart, this might result in several minutes of waiting time (depending on flash size and erase speed).

    • rpi_pico: Added a flash driver for the Raspberry Pi Pico platform.

    • STM32 OSPI: sfdp-bfp table and jedec-id can now be read from device tree and override the flash content if required.

    • STM32 OSPI: Now supports DMA transfer on STM32U5.

    • STM32: Flash driver was revisited to simplify reuse of driver for new series, taking advantage of device tree compatibles.

  • FPGA

    • Added preliminary support for the Lattice iCE40.

    • Added Qomu board sample.

  • GPIO

    • Atmel SAM: Added support to configure Open-Drain pins

    • Added driver for nPM6001 PMIC GPIOs

    • Added NXP S32 GPIO (SIUL2) driver

  • hwinfo

    • Added hwinfo_get_device_id for ESP32-C3

    • Added reset cause for iwdg and wwdg for STM32H7 and MP1

  • I2C

    • SAM0 Fixed spurious trailing data by moving stop condition from thread into ISR

    • I2C Shell command adds ability to configure bus speed through i2c speed

    • ITE usage of instruction local memory support

    • NPCX bus recovery on transaction timeout

    • ITE log status of registers on transfer failure

    • ESP32 enabled configuring a hardware timeout to account for longer durations of clock stretching

    • ITE fixed bug where an operation was done outside of the driver mutex

    • NRFX TWIM Made transfer timeout configurable

    • DW Bug fix for clearing FIFO on initialization

    • NPCX simplified smb bank register usage

    • NXP LPI2C enabled target mode

    • NXP FlexComm Added semaphore for shared usage of bus

    • I2C Added support for dumping messages in the log for all transactions, reads and writes

    • STM32: Slave configuration now supports 10-bit addressing.

    • STM32: Now support power management. 3 modes supported: CONFIG_PM, CONFIG_PM_DEVICE, CONFIG_PM_DEVICE_RUNTIME.

    • STM32: Domain clock can now be configured using device tree

  • I3C

    • Added a new target device API i3c_target_tx_write() to explicit write to TX FIFO.

    • GETMRL and GETMWL are both optional in i3c_device_basic_info_get() as MRL and MWL are optional according to I3C specification.

    • Added a new driver to support Cadence I3C controller.

  • Interrupt Controller

    • STM32: Driver configuration and initialization is now based on device tree

    • Added NXP S32 External Interrupt Controller (SIUL2) driver.

  • IPM

    • ipm_stm32_ipcc: fixed an issue where interrupt mask is not cleaned correctly, resulting in infinite TXF interrupts.

  • MBOX

    • Added NXP S32 Message Receive Unit (MRU) driver.

  • PCIE

    • Support for accessing I/O BARs, which was previously removed, is back.

    • Added new API pcie_scan() to scan for devices.

      • This iterates through the buses and devices which are expected to exist. The old method was to try all possible combination of buses and devices to determine if there is a device there. pci_init() and pcie_bdf_lookup() have been updated to use this new API.

      • pcie_scan() also introduces a callback mechanism for when a new device has been discovered.

  • Pin control

    • Common pin control properties are now defined at root level in a single file: dts/bindings/pinctrl/pincfg-node.yaml. Pin control bindings are expected to include it at the level they need. For example, drivers using the grouping representation approach need to include it at grandchild level, while drivers using the node approach need to include it at the child level. This change will only impact out-of-tree pin control drivers, since all in-tree drivers have been updated.

    • Added NXP S32 SIUL2 driver

    • Added Nuvoton NuMicro driver

    • Added Silabs Gecko driver

    • Added support for i.MX93 in the i.MX driver

    • Added support for GD32L23x/GD32A50x in the Gigadevice driver

  • PWM

    • Atmel SAM: Added support to select pin polarity

    • Added driver for NXP PCA9685 LED controller

  • Regulators

    • Completed an API overhaul so that devices like PMICs can be supported. The API now offers a clear and concise API that allows to perform the following operations:

      • Enable/disable regulator output (reference counted)

      • List supported voltages

      • Get/set operating voltage

      • Get/set maximum current

      • Get/set operating mode

      • Obtain errors, e.g. overcurrent.

      The devicetree part maintains compatibility with Linux bindings, for example, the following properties are well supported:

      • regulator-boot-on

      • regulator-always-on

      • regulator-min-microvolt

      • regulator-max-microvolt

      • regulator-min-microamp

      • regulator-max-microamp

      • regulator-allowed-modes

      • regulator-initial-mode

      A common driver class layer takes care of the common functionality so that driver implementations are kept simple. For example, allowed voltage ranges are verified before calling into the driver.

      An experimental parent API to configure DVS (Dynamic Voltage Scaling) has also been introduced.

    • Refactored NXP PCA9420 driver to align with the new API.

    • Added support for nPM6001 PMIC (LDO and BUCK converters).

    • Added support for nPM1100 PMIC (allows to dynamically change its mode).

    • Added a new test that allows to verify regulator output voltage using the ADC API.

    • Added a new test that checks API behavior provided we have a well-behaved driver.

  • Reset

    • STM32: STM32 reset driver is now available. Devices reset line configuration should be done using device tree.

  • SDHC

    • i.MX RT USDHC:

      • Support HS400 and HS200 mode. This mode is used with eMMC devices, and will enable high speed operation for those cards.

      • Support DMA operation on SOCs that do not support non-cacheable memory, such as the RT595. DMA will enable higher performance SD modes, such as HS400 and SDR104, to reliably transfer data using the SD host controller

  • Sensor

    • Refactored all drivers to use SENSOR_DEVICE_DT_INST_DEFINE to enable a new sensor info iterable section and shell command. See CONFIG_SENSOR_INFO.

    • Refactored all sensor devicetree bindings to inherit new base sensor device properties in dts/bindings/sensor/sensor-device.yaml.

    • Added sensor attribute support to the shell.

    • Added ESP32 and RaspberryPi Pico die temperature sensor drivers.

    • Added TDK InvenSense ICM42688 six axis IMU driver.

    • Added TDK InvenSense ICP10125 pressure and temperature sensor driver.

    • Added AMS AS5600 magnetic angle sensor driver.

    • Added AMS AS621x temperature sensor driver.

    • Added HZ-Grow R502A fingerprint sensor driver.

    • Enhanced FXOS8700, FXAS21002, and BMI270 drivers to support SPI in addition to I2C.

    • Enhanced ST LIS2DW12 driver to support free fall detection.

    • rpi_pico: Added die temperature sensor driver.

    • STM32 family Quadrature Decoder driver was added. Only enabled on STM32F4 for now.

  • Serial

    • Atmel SAM: UART/USART: Added support to configure driver at runtime

    • STM32: DMA now supported on STM32U5 series.

    • uart_altera_jtag: added support for Nios-V UART.

    • uart_esp32: added support asynchronous operation.

    • uart_gecko: added support for pinctrl.

    • uart_mchp_xec: now supports UART on MEC15xx SoC.

    • uart_mcux_flexcomm: added support for runtime configuration.

    • uart_mcux_lpuart: added support for RS-485.

    • uart_numicro: uses pinctrl to configure UART pins.

    • uart_pl011: added support for pinctrl.

    • uart_rpi_pico: added support for runtime configuration.

    • uart_xmc4xxx: added support for interrupt so it can now be interrupt driven. Also added support for FIFO.

    • New UART drivers are added:

      • Cadence IP6528 UART.

      • NXP S32 LINFlexD UART.

      • OpenTitan UART.

      • QuickLogic USBserialport_S3B.

  • SPI

    • Added dma support for GD32 driver.

    • Atmel SAM:

      • Added support to transfers using DMA.

      • Added support to loopback mode for testing purposes.

    • Added NXP S32 SPI driver.

  • Timer

    • Corrected CPU numbering on SMP RISC-V systems using the mtime device

    • Added support for OpenTitan’s privileged timer device to riscv_machine_timer

    • Refactored SYS_CLOCK_EXISTS such that it always matches the existence of a timer device in kconfig

    • Significant rework to nrf_rtc_timer with multiple fixes

    • Fixed prescaler correction in stm32_lptim driver and fix race with auto-reload

  • USB

    • STM32F1: Clock bus configuration is not done automatically by driver anymore. It is user’s responsibility to configure the proper bus prescaler using clock_control device tree node to achieve a 48MHz bus clock. Note that, in most cases, core clock is 72MHz and default prescaler configuration is set to achieve 48MHz USB bus clock. Prescaler only needs to be configured manually when core clock is already 48MHz.

    • STM32 (non F1): Clock bus configuration is now expected to be done in device tree using clocks node property. When a dedicated HSI 48MHz clock is available on target, is it configured by default as the USB bus clock, but user has the ability to select another 48MHz clock source. When no HSI48 is available, a specific 48MHz bus clock source should be configured by user.

    • STM32: Now supports usb_dc_detach() and usb_dc_wakeup_request().

    • STM32: Vbus sensing is now supported and determined based on the presence of the hardware detection pin(s) in the device tree. E.g: pinctrl-0 = <&usb_otg_fs_vbus_pa9 …>;

    • RPi Pico: fixed buffer status handling, fixed infinite unhandled irq retriggers, fixed DATA PID toggle and control transfer handling.

    • NXP: Enabled high speed support, fixed endpoint buffer write operation.

    • nRF USBD: Removed HAL driver uninit on detach, fixed endpoints disable on USB stack disable.

    • Added new experimental USB device controller (UDC) API and implementation for nRF USBD, Kinetis USBFSOTG, and virtual controllers.

    • Added new experimental USB host controller (UDC) API and implementation for MAX3421E and virtual controllers.

  • Watchdog

    • Added driver for nPM6001 PMIC Watchdog.

    • Added free watchdog driver for GigaDevice GD32 SoCs.

    • Added window watchdog driver for GigaDevice GD32 SoCs.

    • Added NXP S32 Software Watchdog Timer driver.


  • CoAP:

    • Implemented insertion of a CoAP option at arbitrary position.

  • Ethernet:

    • Fixed AF_PACKET/SOCK_RAW/IPPROTO_RAW sockets on top of Ethernet L2.

    • Added support for setting Ethernet MAC address with net shell.

    • Added check for return values of the driver start/stop routines when bringing Ethernet interface up.

    • Added unknown_protocol statistic for packets with unrecognized protocol field, instead of using error for this purpose.

    • Added NXP S32 NETC Ethernet driver.

  • HTTP:

    • Reworked HTTP headers: moved methods to a separate header, added status response codes header and grouped HTTP headers in a subdirectory.

    • Used zsock_poll() for HTTP timeout instead of a delayed work.

  • ICMPv4:

    • Added support to autogenerate Echo Request payload.

  • ICMPv6:

    • Added support to autogenerate Echo Request payload.

    • Fixed stats counting for ND packets.

  • IEEE802154:

    • Improved short address support.

    • Improved IEEE802154 context thread safety.

    • Decoupled IEEE802154 parameters from net_pkt into net_pkt_cb_ieee802154.

    • Multiple other minor fixes/improvements.

  • IPv4:

    • IPv4 packet fragmentation support has been added, this allows large packets to be split up before sending or reassembled during receive for packets that are larger than the network device MTU. This is disabled by default but can be enabled with CONFIG_NET_IPV4_FRAGMENT.

    • Added support for setting/reading DSCP/ECN fields.

    • Fixed packet leak in IPv4 address auto-configuration procedure.

    • Added support for configuring IPv4 addresses with net ipv4 shell command.

    • Zephyr now adds IGMP all systems address to all IPv4 network interfaces by default.

  • IPv6:

    • Made it possible to add route to router’s link local address.

    • Added support for setting/reading DSCP/ECN fields.

    • Improved test coverage for IPv6 fragmentation.

    • Added support for configuring IPv6 addresses with net ipv6 shell command.

    • Added support for configuring IPv6 routes with net route shell command.

  • LwM2M:

    • Renamed LWM2M_RD_CLIENT_EVENT_REG_UPDATE_FAILURE to LWM2M_RD_CLIENT_EVENT_REG_TIMEOUT. This event is now used in case of registration timeout.

    • Added new LwM2M APIs for historical data storage for LwM2M resource.

    • Updated LwM2M APIs to use const pointers when possible.

    • Added shell command to lock/unlock LwM2M registry.

    • Added shell command to enable historical data cache for a resource.

    • Switched to use zsock_* functions internally.

    • Added uCIFI LPWAN (ID 3412) object implementation.

    • Added BinaryAppDataContainer (ID 19) object implementation.

    • Deprecated CONFIG_LWM2M_RD_CLIENT_SUPPORT, as it’s now considered as an integral part of the LwM2M library.

    • Added support for SenML Object Link data type.

    • Fixed a bug causing incorrect ordering of the observation paths.

    • Deprecated string based LwM2M APIs. LwM2M APIs now use lwm2m_obj_path to represent object/resource paths.

    • Refactored lwm2m_client sample by splitting specific functionalities into separate modules.

    • Multiple other minor fixes within the LwM2M library.

  • Misc:

    • Updated various networking test suites to use the new ztest API.

    • Added redirect support for big_http_download sample and updated the server URL for TLS variant.

    • Fixed memory leak in net udp shell command.

    • Fixed cloning of LL address for net_pkt.

    • Added support for QoS and payload size setting in net ping shell command.

    • Added support for aborting net ping shell command.

    • Introduced carrier and dormant management on network interfaces. Separated interface administrative state from operational state.

    • Improved DHCPv4 behavior with multiple DHCPv4 servers in the network.

    • Fixed net_mgmt event size calculation.

    • Added CONFIG_NET_LOOPBACK_MTU option to configure loopback interface MTU.

    • Reimplemented the IP/UDP/TCP checksum calculation to speed up the processing.

    • Removed CONFIG_NET_CONFIG_SETTINGS use from test cases to improve test execution on real platforms.

    • Added MQTT-SN library and sample.

    • Fixed variable buffer length configuration (CONFIG_NET_BUF_VARIABLE_DATA_SIZE).

    • Fixed IGMPv2 membership report destination address.

    • Added mutex protection for the connection list handling.

    • Separated user data pointer from FIFO reserved space in net_context.

    • Added input validation for net pkt shell command.

  • OpenThread:

  • SNTP:

    • Switched to use zsock_* functions internally.

    • Fixed the library operation with IPv4 disabled.

  • Sockets:

    • Fixed a possible memory leak on failed TLS socket creation.

  • TCP:

    • Extended the default TCP out-of-order receive queue timeout to 2 seconds.

    • Reimplemented TCP ref counting, to prevent situation, where TCP connection context could be released prematurely.

  • Websockets:

    • Reimplemented websocket receive routine to fix several issues.

    • Implemented proper websocket close procedure.

    • Fixed a bug where websocket would overwrite the mutex used by underlying TCP socket.

  • Wi-Fi:

    • Added support for power save configuration.

    • Added support for regulatory domain configuration.

    • Added support for power save timeout configuration.

  • zperf

    • Added option to set QoS for zperf.

    • Fixed out of order/lost packets statistics.

    • Defined a public API for the library to allow throughput measurement without shell enabled.

    • Added an option for asynchronous upload.


  • New experimental USB support:

    • Added new USB device stack (device_next), class implementation for CDC ACM and BT HCI USB transport layer.

    • Added initial support for USB host

  • USB device stack (device):

    • Removed transfer cancellation on bus suspend.

    • Reworked disabling all endpoints on stack disable to allow re-enabling USB device stack.

    • Revised endpoint enable/disable on alternate setting.

    • Improved USB DFU support with WinUSB on Windows.

    • Added check to prevent recursive logging loop and allowed to send more than one byte using poll out in CDC ACM class implementation.

    • Corrected IAD and interface descriptors, removed unnecessary CDC descriptors, and fixed packet reception in RNDIS ethernet implementation.

    • Implemented cache synchronization after write operations in USB MSC class.



New general-purpose macros:

New special-purpose macros introduced for the GPIO hogs feature (see drivers/gpio/gpio_hogs.c):

The following deprecated macros were removed:




New bindings:

Removed bindings:

  • Generic or vendor-independent:

    • regulator-pmic

  • Intel Corporation (intel):

    • intel,adsp-lps

  • NXP Semiconductors (nxp):

    • nxp,imx-flexspi-hyperram

  • STMicroelectronics (st):

    • st,stm32f0-flash-controller

    • st,stm32f3-flash-controller

    • st,stm32l0-flash-controller

    • st,stm32l1-flash-controller

    • st,stm32u5-flash-controller

Modified bindings:

  • Generic or vendor-independent:

    • All sensor devices now have a friendly-name property, which is a human-readable string describing the sensor. See dts/bindings/sensor/sensor-device.yaml for more information.

    • All DMA controller devices have had their dma-buf-alignment properties renamed to dma-buf-addr-alignment.

      Additionally, all DMA controller devices have new dma-buf-size-alignment and dma-copy-alignment properties.

      See dts/bindings/dma/dma-controller.yaml for more information.

    • ns16550:

      • new property: vendor-id

      • new property: device-id

      • property reg is no longer required

    • pci-host-ecam-generic:

      • new property: interrupt-map-mask

      • new property: interrupt-map

      • new property: bus-range

    • regulator-fixed:

      • removed property: supply-gpios

      • removed property: vin-supply

    • gpio-keys:

      • new property: debounce-interval-ms

  • Altera Corp. (altr):

  • ARM Ltd. (arm):

    • arm,pl011:

      • new property: pinctrl-0

      • new property: pinctrl-1

      • new property: pinctrl-2

      • new property: pinctrl-3

      • new property: pinctrl-4

      • new property: pinctrl-names

  • Atmel Corporation (atmel):

    • atmel,sam-pwm:

      • specifier cells for space “pwm” are now named: [‘channel’, ‘period’, ‘flags’] (old value: [‘channel’, ‘period’])

      • property #pwm-cells const value changed from 2 to 3

    • atmel,sam-spi:

      • new property: loopback

  • Espressif Systems (espressif):

  • GigaDevice Semiconductor (gd):

    • gd,gd32-dma:

      • specifier cells for space “dma” are now named: [‘channel’, ‘config’] (old value: [‘channel’])

      • new property: gd,mem2mem

      • removed property: resets

      • removed property: reset-names

      • property #dma-cells const value changed from 1 to 2

  • ILI Technology Corporation (ILITEK) (ilitek):

    • ilitek,ili9341 (on spi bus):

      • property disctrl default value changed from [10, 130, 39] to [10, 130, 39, 4]

  • Infineon Technologies (infineon):

    • infineon,xmc4xxx-uart:

      • new property: fifo-start-offset

      • new property: fifo-tx-size

      • new property: fifo-rx-size

  • Intel Corporation (intel):

  • ITE Tech. Inc. (ite):

    • ite,it8xxx2-pinctrl-func:

      • new property: pp-od-mask

      • new property: pullup-mask

      • new property: gpio-group

      • property volt-sel-mask is no longer required

      • property func4-gcr is no longer required

      • property func3-en-mask is no longer required

      • property func3-gcr is no longer required

      • property func4-en-mask is no longer required

      • property volt-sel is no longer required

  • JEDEC Solid State Technology Association (jedec):

    • jedec,spi-nor (on spi bus):

      • new property: mxicy,mx25r-power-mode

  • Microchip Technology Inc. (microchip):

    • microchip,xec-uart:

      • new property: wakerx-gpios

    • microchip,xec-pcr:

      • new property: clk32kmon-period-min

      • new property: clk32kmon-period-max

      • new property: clk32kmon-duty-cycle-var-max

      • new property: clk32kmon-valid-min

      • new property: xtal-enable-delay-ms

      • new property: pll-lock-timeout-ms

      • new property: clkmon-bypass

      • new property: internal-osc-disable

      • new property: pinctrl-0

      • new property: pinctrl-names

      • new property: pinctrl-1

      • new property: pinctrl-2

      • new property: pinctrl-3

      • new property: pinctrl-4

      • property interrupts is no longer required

    • microchip,xec-qmspi-ldma:

      • new property: port-sel

      • new property: chip-select

      • removed property: port_sel

      • removed property: chip_select

      • property lines enum value changed from None to [1, 2, 4]

  • Nordic Semiconductor (nordic):

  • Nuvoton Technology Corporation (nuvoton):

    • nuvoton,numicro-uart:

      • new property: pinctrl-0

      • new property: pinctrl-1

      • new property: pinctrl-2

      • new property: pinctrl-3

      • new property: pinctrl-4

      • new property: pinctrl-names

    • nuvoton,adc-cmp:

      • new property: status

      • new property: compatible

      • new property: reg

      • new property: reg-names

      • new property: interrupts

      • new property: interrupts-extended

      • new property: interrupt-names

      • new property: interrupt-parent

      • new property: label

      • new property: clocks

      • new property: clock-names

      • new property: #address-cells

      • new property: #size-cells

      • new property: dmas

      • new property: dma-names

      • new property: io-channel-names

      • new property: mboxes

      • new property: mbox-names

      • new property: wakeup-source

      • new property: power-domain

  • NXP Semiconductors (nxp):

    • nxp,kinetis-lpuart:

      • new property: nxp,rs485-mode

      • new property: nxp,rs485-de-active-low

    • nxp,fxas21002 (on i2c bus):

      • new property: reset-gpios

    • nxp,imx-pwm:

      • specifier cells for space “pwm” are now named: [‘channel’, ‘period’, ‘flags’] (old value: [‘channel’, ‘period’])

      • new property: nxp,prescaler

      • new property: nxp,reload

      • property #pwm-cells const value changed from 2 to 3

    • nxp,imx-usdhc:

      • new property: mmc-hs200-1_8v

      • new property: mmc-hs400-1_8v

    • nxp,lpc-sdif:

      • new property: mmc-hs200-1_8v

      • new property: mmc-hs400-1_8v

  • QEMU, a generic and open source machine emulator and virtualizer (qemu):

    • qemu,ivshmem:

      • new property: vendor-id

      • new property: device-id

  • Renesas Electronics Corporation (renesas):

    • renesas,smartbond-uart:

      • property current-speed enum value changed from [1200, 2400, 4800, 9600, 14400, 19200, 28800, 38400, 57600, 115200, 230400, 460800, 921600, 1000000] to [4800, 9600, 14400, 19200, 28800, 38400, 57600, 115200, 230400, 500000, 921600, 1000000, 2000000]

  • Silicon Laboratories (silabs):

    • silabs,gecko-usart:

      • new property: pinctrl-0

      • new property: pinctrl-1

      • new property: pinctrl-2

      • new property: pinctrl-3

      • new property: pinctrl-4

      • new property: pinctrl-names

      • property location-rx is no longer required

      • property location-tx is no longer required

      • property peripheral-id is no longer required

    • silabs,gecko-gpio-port:

      • property peripheral-id is no longer required

    • silabs,gecko-spi-usart:

      • new property: pinctrl-0

      • new property: pinctrl-1

      • new property: pinctrl-2

      • new property: pinctrl-3

      • new property: pinctrl-4

      • new property: pinctrl-names

      • property location-clk is no longer required

      • property location-rx is no longer required

      • property location-tx is no longer required

      • property peripheral-id is no longer required

  • Sitronix Technology Corporation (sitronix):

  • Synopsys, Inc. (snps):

    • snps,designware-i2c:

      • new property: vendor-id

      • new property: device-id

      • property reg is no longer required

  • STMicroelectronics (st):

    • st,stm32-adc:

      • the has-temp-channel, has-vref-channel and has-vbat-channel properties were respectively replaced by temp-channel, vref-channel and vbat-channel

    • st,stm32-ethernet:

      • the built-in driver for this compatible now supports the local-mac-address and zephyr,random-mac-address properties for setting MAC addresses, and the associated Kconfig options (CONFIG_ETH_STM32_HAL_RANDOM_MAC, CONFIG_ETH_STM32_HAL_USER_STATIC_MAC) are now deprecated

    • st,stm32-qspi-nor (on qspi bus):

      • new property: reset-cmd

      • new property: reset-cmd-wait

    • st,stm32-uart:

      • new property: resets

      • new property: tx-rx-swap

      • new property: reset-names

    • st,stm32-usart:

      • new property: resets

      • new property: tx-rx-swap

      • new property: reset-names

    • st,stm32-lpuart:

      • new property: resets

      • new property: tx-rx-swap

      • new property: reset-names

    • st,stm32-exti:

      • new property: num-lines

      • new property: line-ranges

      • new property: interrupt-controller

      • new property: #interrupt-cells

      • property interrupts is now required

      • property interrupt-names is now required

    • st,stm32-ospi:

      • property clock-names is now required

    • st,stm32f105-pll2-clock:

      • new property: otgfspre

    • st,stm32f105-pll-clock:

      • new property: otgfspre

    • st,stm32f100-pll-clock:

      • new property: otgfspre

    • st,stm32f1-pll-clock:

      • property usbpre type changed from int to boolean

    • st,stm32-lse-clock:

      • new property: lse-bypass

    • st,lis2dh12 (on i2c bus):

      • new property: anym-no-latch

      • new property: anym-mode

    • st,lsm6dso (on i2c bus):

      • new property: drdy-pulsed

    • st,lis2dh (on i2c bus):

      • new property: anym-no-latch

      • new property: anym-mode

    • st,lsm303agr-accel (on spi bus):

      • new property: anym-no-latch

      • new property: anym-mode

    • st,lis3dh (on i2c bus):

      • new property: anym-no-latch

      • new property: anym-mode

    • st,lsm6dso (on spi bus):

      • new property: drdy-pulsed

    • st,lis2dw12 (on spi bus):

      • new property: odr

      • new property: ff-duration

      • new property: ff-threshold

    • st,lsm6dso32 (on spi bus):

      • new property: drdy-pulsed

    • st,lsm303dlhc-accel (on i2c bus):

      • new property: anym-no-latch

      • new property: anym-mode

    • st,lis2dh (on spi bus):

      • new property: anym-no-latch

      • new property: anym-mode

    • st,lis2dw12 (on i2c bus):

      • new property: odr

      • new property: ff-duration

      • new property: ff-threshold

    • st,lsm303agr-accel (on i2c bus):

      • new property: anym-no-latch

      • new property: anym-mode

    • st,lsm6dso32 (on i2c bus):

      • new property: drdy-pulsed

    • st,stm32-sdmmc:

      • new property: resets

      • new property: reset-names

    • st,stm32-ucpd:

      • new property: dead-battery

      • new property: pinctrl-0

      • new property: pinctrl-names

      • new property: pinctrl-1

      • new property: pinctrl-2

      • new property: pinctrl-3

      • new property: pinctrl-4

    • st,stm32-timers:

      • new property: resets

      • new property: reset-names

    • st,stm32-lptim:

      • new property: st,static-prescaler

      • new property: reset-names

    • st,stm32-usb:

      • removed property: enable-pin-remap

  • Texas Instruments (ti):

    • ti,ina230 (on i2c bus):

      • new property: current-lsb-microamps

      • new property: rshunt-milliohms

      • new property: alert-gpios

      • removed property: irq-gpios

      • removed property: current-lsb

      • removed property: rshunt

    • ti,ina237 (on i2c bus):

      • new property: current-lsb-microamps

      • new property: rshunt-milliohms

      • new property: alert-gpios

      • removed property: irq-gpios

      • removed property: current-lsb

      • removed property: rshunt

  • A stand-in for a real vendor which can be used in examples and tests (vnd):

    • vnd,pinctrl:

      • new property: bias-disable

      • new property: bias-high-impedance

      • new property: bias-bus-hold

      • new property: bias-pull-up

      • new property: bias-pull-down

      • new property: bias-pull-pin-default

      • new property: drive-push-pull

      • new property: drive-open-drain

      • new property: drive-open-source

      • new property: drive-strength

      • new property: drive-strength-microamp

      • new property: input-enable

      • new property: input-disable

      • new property: input-schmitt-enable

      • new property: input-schmitt-disable

      • new property: input-debounce

      • new property: power-source

      • new property: low-power-enable

      • new property: low-power-disable

      • new property: output-disable

      • new property: output-enable

      • new property: output-low

      • new property: output-high

      • new property: sleep-hardware-state

      • new property: slew-rate

      • new property: skew-delay

  • Zephyr-specific binding (zephyr):



  • In order to avoid name conflicts with devices that may be defined at board level, it is advised, specifically for shields devicetree descriptions, to provide a device nodelabel in the form <device>_<shield>. In-tree shields have been updated to follow this recommendation.

  • Others

    • STM32F1 SoCs

      • Added new pinctrl definitions for STM32F1xx PWM input. In PWM capture mode STM32F1xx pins have to be configured as input and not as alternate. The new names takes the form tim1_ch1_pwm_in_pa8 for example.

      • Renamed pinctrl definitions for STM32F1xx PWM output to differentiate them from newly created inputs. The new names takes the form tim1_ch1_pwm_out_pa8 instead of tim1_ch1_pwm_pa8.

Libraries / Subsystems

  • C Library

    • Newlib nano variant is no longer selected by default when CONFIG_NEWLIB_LIBC is selected. CONFIG_NEWLIB_LIBC_NANO must now be explicitly selected in order to use the nano variant.

    • Picolibc now supports all architectures supported by Zephyr.

    • Added C11 aligned_alloc support to the minimal libc.

  • C++ Library

    • C++ support in Zephyr is no longer considered a “subsystem” because it mainly consists of the C++ ABI runtime library and the C++ standard library, which are “libraries” that are dissimilar to the existing Zephyr subsystems. C++ support components are now located in lib/cpp as “C++ library.”

    • C++ ABI runtime library components such as global constructor/destructor and initialiser handlers, that were previously located under subsys/cpp, have been moved to lib/cpp/abi in order to provide a clear separation between the C++ ABI runtime library and the C++ standard library.

    • C++ minimal library components have been moved to lib/cpp/minimal.

    • C++ tests have been moved to tests/lib/cpp.

    • C++ samples have been moved to samples/cpp.

    • CONFIG_CPLUSPLUS has been renamed to CONFIG_CPP.


    • CONFIG_RTTI has been renamed to CONFIG_CPP_RTTI.

    • CONFIG_LIB_CPLUSPLUS is deprecated. A toolchain-specific C++ standard library Kconfig option from CONFIG_LIBCPP_IMPLEMENTATION should be selected instead.

    • Zephyr subsystems and modules that require the features from the full C++ standard library (e.g. Standard Template Library) can now select CONFIG_REQUIRES_FULL_LIBC, which automatically selects a compatible C++ standard library.

    • Introduced CONFIG_CPP_MAIN to support defining main() function in a C++ source file. Enabling this option makes the Zephyr kernel invoke int main(void), which is required by the ISO C++ standards, as opposed to the Zephyr default void main(void).

    • Added no-throwing implementation of new operator to the C++ minimal library.

    • Added support for new operator with alignment request (C++17) to the C++ minimal library.

    • Added GNU C++ standard library support with Picolibc when using a suitably configured toolchain (e.g. the upcoming Zephyr SDK 0.16.0 release).

  • Cache

  • DSP

    • Introduced DSP (digital signal processing) subsystem with CMSIS-DSP as the default backend.

    • CMSIS-DSP now supports all architectures supported by Zephyr.

  • File systems

    • Added new API call fs_mkfs.

    • Added new sample samples/subsys/fs/format.

    • FAT FS driver has been updated to version 0.15 w/patch1.

    • Added the option to disable CRC checking in Flash Circular Buffer (FCB) by enabling the Kconfig option CONFIG_FCB_ALLOW_FIXED_ENDMARKER and setting the FCB_FLAGS_CRC_DISABLED flag in the fcb struct.

  • IPC

    • Added ipc_rpmsg_deinit(), ipc_service_close_instance() and ipc_static_vrings_deinit() functions

    • Added deregister API support for icmsg backend

    • Added a multi-endpoint feature to icmsg backend

    • Added no-copy features to icmsg backend

  • ISO-TP

    • Rewrote the ISO-TP API to not reuse definitions from the CAN controller API.

  • Logging

    • Added support for logging on multiple domains.

    • CONFIG_LOG_PRINTK is now by default enabled which means that when logging is enabled then printk is by directed to the logging subsystem.

    • Added option to use custom logging header.

  • Management

    • MCUmgr functionality deprecated in 3.1 has been removed: CONFIG_FS_MGMT_UL_CHUNK_SIZE, CONFIG_IMG_MGMT_UL_CHUNK_SIZE, CONFIG_OS_MGMT_ECHO_LENGTH

    • MCUmgr fs_mgmt issue with erasing a file prior to writing the first block of data has been worked around by only truncating/deleting the file data if the file exists. This can help work around an issue whereby logging is enabled and the command is sent on the same UART as the logging system, in which a filesystem error was emitted.

    • A MCUmgr bug when using the smp_svr sample with Bluetooth transport that could have caused a stack overflow has been fixed.

    • A MCUmgr issue with Bluetooth transport that could cause a deadlock of the mcumgr thread if the remote device disconnected before the output message was sent has been fixed.

    • A MCUmgr img_mgmt bug whereby the state of an image upload could persist when it was no longer valid (e.g. after an image erase command) has been fixed.

    • MCUmgr fs_mgmt command has been added that allows querying/listing the supported hash/checksum types.

    • MCUmgr Bluetooth transport will now clear unprocessed commands sent if a remote device disconnects instead of processing them.

    • A new MCUmgr transport function pointer has been added which needs registering in smp_transport_init for removing invalid packets for connection-orientated transports. If this is unimplemented, the function pointer can be set to NULL.

    • MCUmgr command handler definitions have changed, the mgmt_ctxt struct has been replaced with the smp_streamer struct, the zcbor objects need to replace cnbe object access with writer and cnbd object access with reader to successfully build.

    • MCUmgr callback system has been reworked with a unified singular interface which supports status passing to the handler (MCUmgr Callbacks).

    • MCUmgr subsystem directory structure has been flattened and contents of the lib subdirectory has been redistributed into following directories:


      MCUmgr area


      MCUmgr management functions, group registration, and so on;


      Simple Management Protocol processing;


      Transport support and transport API;


      Command groups, formerly lib/cmd; each group, which has Zephyr built in support has its own directory here;


      Utilities used by various subareas of MCUmgr.

      Public API interfaces for above areas are now exported through zephyr_interface, and headers for them reside in zephyr/mgmt/mcumgr/<mcumgr_subarea>/. For example to access mgmt API include <zephyr/mgmt/mcumgr/mgmt/mgmt.h>.

      Private headers for above areas can be accessed, when required, using paths: mgmt/mcumgr/mgmt/<mcumgr_subarea>/.

    • MCUmgr os_mgmt info command has been added that allows querying details on the kernel and application, allowing application-level extensibility see OS/Application Info for details.

    • MCUMgr CONFIG_APP_LINK_WITH_MCUMGR has been removed as it has not been doing anything.

    • MCUmgr Kconfig option names have been standardised. Script scripts/utils/migrate_mcumgr_kconfigs.py has been provided to make transition to new Kconfig options easier. Below table provides information on old names and new equivalents:

      Old Kconfig option name

      New Kconfig option name



































































































































































    • MCUmgr responses where rc (result code) is 0 (no error) will no longer be present in responses and in cases where there is only an rc result, the resultant response will now be an empty CBOR map. The old behaviour can be restored by enabling CONFIG_MCUMGR_SMP_LEGACY_RC_BEHAVIOUR.

    • MCUmgr now has log outputting on most errors from the included fs, img, os, shell, stat and zephyr_basic group commands. The level of logging can be controlled by adjusting: CONFIG_MCUMGR_GRP_FS_LOG_LEVEL, CONFIG_MCUMGR_GRP_IMG_LOG_LEVEL, CONFIG_MCUMGR_GRP_OS_LOG_LEVEL, CONFIG_MCUMGR_GRP_SHELL_LOG_LEVEL, CONFIG_MCUMGR_GRP_STAT_LOG_LEVEL and CONFIG_MCUMGR_GRP_ZBASIC_LOG_LEVEL.

    • MCUmgr img_mgmt has a new field which is sent in the final packet (if CONFIG_IMG_ENABLE_IMAGE_CHECK is enabled) named match which is a boolean and is true if the uploaded data matches the supplied hash, or false otherwise.

    • MCUmgr img_mgmt will now skip receiving data if the provided hash already matches the hash of the data present (if CONFIG_IMG_ENABLE_IMAGE_CHECK is enabled) and finish the upload operation request instantly.

    • MCUmgr img_mgmt structs are now packed, which fixes a fault issue on processors that do not support unaligned memory access.

    • If MCUmgr is used with the shell transport and printk() functionality is used, there can be an issue whereby the printk() calls output during a MCUmgr frame receive, this has been fixed by default in zephyr by routing printk() calls to the logging system, For user applications, CONFIG_LOG_PRINTK should be enabled to include this fix.

    • A bug when MCUmgr shell transport is used (issue was observed over USB CDC but could also occur with UART) whereby the default shell receive ring buffer is insufficient has been fixed by making the default size 256 bytes instead of 64 when the shell MCUmgr transport is selected.

    • UpdateHub:

      • The integrity check was reworked to allow use by other libraries. Since then UpdateHub uses mbedTLS library as default crypto library.

      • Added a new Storage Abstraction to isolate both flash operations and MCUboot internals.

      • The UpdateHub User API was moved as a Zephyr public API and the userspace now is available. This added updatehub_confirm() and updatehub_reboot() functions.

  • LwM2M

    • The lwm2m_senml_cbor_* files have been regenerated using zcbor 0.6.0.


    • Harmonized posix type definitions across the minimal libc, newlib and picolibc.

      • Abstract pthread_t, pthread_key_t, pthread_cond_t, pthread_mutex_t, as uint32_t.


    • Allowed non-prefixed standard include paths with CONFIG_POSIX_API.

      • I.e. #include <unistd.h> instead of #include <zephyr/posix/unistd.h>.

      • Primarily to ease integration with external libraries.

      • Internal Zephyr code should continue to use prefixed header paths.

    • Enabled eventfd(), getopt() by default with CONFIG_POSIX_API.

    • Moved / renamed header files to align with POSIX specifications.

      • E.g. move fcntl.h, sys/stat.h from the minimal libc into the include/zephyr/posix directory. Rename posix_sched.h to sched.h.

      • Move O_ACCMODE, O_RDONLY, O_WRONLY, O_WRONLY, to fcntl.h.



  • SD Subsystem

    • Added support for eMMC protocol in Zephyr.

      • Speed modes up to HS400 are supported using 1.8v operation.

      • Additional protocol tests have been added to verify eMMC functionality.

      • Disk subsystem tests have been updated to function with eMMC.

    • Card and host combinations that cannot utilize UHS (ultra high speed) mode will now use 4 bit bus width when possible. This will greatly improve performance for these systems.

  • Settings

    • Replaced all k_panic() invocations within settings backend initialization with returning / propagating error codes.

  • Shell

    • New features:

      • SHELL_AUTOSTART configuration option. When SHELL_AUTOSTART is set to n, the shell is not started after boot but can be enabled later from the application code.

      • Added support for setting the help description for each entry in a dictionary.

    • Bugfix:

      • Updated to clear command buffer when leaving bypass mode to prevent undefined behaviour on consecutive shell operations.

      • Set RX size default to 256 if shell MCUmgr is enabled.

      • Fixed log message queue size for all backends.

    • Documentation:

      • Added information explaining commands execution.

  • Utilities

  • Zbus


  • Atmel

    • sam0: Added support for SAMC20/21.

    • sam4l: Added US_MR_CHRL_{n}_BIT Register Aliases for USART Driver.

  • GigaDevice

    • Added support for gd32l23x.

    • Added support for gd32a50x.

  • Nordic

    • Updated nrfx to version 2.10.0.

  • STM32

    • stm32cube: updated stm32h7 to cube version V1.11.0.

    • stm32cube: updated stm32l5 to cube version V1.5.0.

    • stm32cube: updated stm32wl to cube version V1.3.0.

  • Espressif

    • Added Ethernet driver support

    • Added light-sleep and deep-sleep support over PM interface

    • Added ADC and DAC driver support

    • Added GDMA driver support


  • Flash Map API drops fa_device_id from flash_area, as it is no longer needed by MCUboot, and has not been populated for a long time now.

Trusted Firmware-M

  • Updated to TF-M 1.7.0 (and MbedTLS 3.2.1).

  • Initial attestation service has been disabled by default due to license issues with the QCBOR dependency. To enable it, set the path for QCBOR via CONFIG_TFM_QCBOR_PATH or set the path to DOWNLOAD.

  • Firmware update sample removed pending update to 1.0 FWU service.

  • psa_crypto sample removed pending resolution of PSA API conflicts w/MbedTLS.


Upgraded zcbor to 0.6.0. Among other things, this brings in a few convenient changes for Zephyr:

  • In the zcbor codebase, the ARRAY_SIZE macro has been renamed to ZCBOR_ARRAY_SIZE to not collide with Zephyr’s ARRAY_SIZE macro.

  • The zcbor codebase now better supports being used in C++ code.

The entire release notes can be found at https://github.com/zephyrproject-rtos/zcbor/blob/0.6.0/RELEASE_NOTES.md


  • Upgraded to Doxygen 1.9.6.

  • It is now possible to link to Kconfig search results.