:orphan:

.. _zephyr_3.3:

Zephyr 3.3.0 (Working Draft)
############################

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

Major enhancements with this release include:

The following sections provide detailed lists of changes by component.

Security Vulnerability Related
******************************

API Changes
***********

Changes in this release
=======================

* Bluetooth: Add 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: :kconfig:option:`CONFIG_BT_PER_ADV_SYNC_TRANSFER_RECEIVER`
  and :kconfig:option:`CONFIG_BT_PER_ADV_SYNC_TRANSFER_SENDER` have been
  added to enable the PAST implementation rather than
  :kconfig:option:`CONFIG_BT_CONN`.
* Flashdisk: :kconfig:option:`CONFIG_DISK_FLASH_VOLUME_NAME`,
  :kconfig:option:`CONFIG_DISK_FLASH_DEV_NAME`,
  :kconfig:option:`CONFIG_DISK_FLASH_START`,
  :kconfig:option:`CONFIG_DISK_FLASH_MAX_RW_SIZE`,
  :kconfig:option:`CONFIG_DISK_ERASE_BLOCK_SIZE`,
  :kconfig:option:`CONFIG_DISK_FLASH_ERASE_ALIGNMENT`,
  :kconfig:option:`CONFIG_DISK_VOLUME_SIZE` and
  :kconfig:option:`CONFIG_DISK_FLASH_SECTOR_SIZE` Kconfig options have been
  removed in favor of new :dtcompatible:`zephyr,flash-disk` devicetree binding.

* Regulator APIs previously located in ``<zephyr/drivers/regulator/consumer.h>``
  are now part of ``<zerphyr/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: Deprecate 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 bootup (this
  feature can be disabled for the UDP transport by setting
  :kconfig:option:`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:

  * :kconfig:option:`CONFIG_BT`
  * :kconfig:option:`CONFIG_BT_PERIPHERAL`

  For CDC or serial transports:

  * :kconfig:option:`CONFIG_CONSOLE`

  For shell transport:

  * :kconfig:option:`CONFIG_SHELL`
  * :kconfig:option:`CONFIG_SHELL_BACKEND_SERIAL`

  For UDP transport:

  * :kconfig:option:`CONFIG_NETWORKING`
  * :kconfig:option:`CONFIG_NET_UDP`

* 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.

Removed APIs in this release
============================

* Removed :kconfig:option:`CONFIG_COUNTER_RTC_STM32_LSE_DRIVE*`
  This should now be configured using the ``driving_capability`` property of
  LSE clock

* Removed :kconfig:option:`CONFIG_COUNTER_RTC_STM32_LSE_BYPASS`
  This should now be configured using the new ``lse_bypass`` property of
  LSE clock

* Removed :kconfig:option:`CONFIG_COUNTER_RTC_STM32_BACKUP_DOMAIN_RESET`

* 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.

Deprecated in this release
==========================

* C++ library Kconfig options have been renamed to improve consistency. See
  below for the list of deprecated Kconfig options and their replacements:

  .. table::
     :align: center

     +----------------------------------------+------------------------------------------------+
     | Deprecated                             | Replacement                                    |
     +========================================+================================================+
     | :kconfig:option:`CONFIG_CPLUSPLUS`     | :kconfig:option:`CONFIG_CPP`                   |
     +----------------------------------------+------------------------------------------------+
     | :kconfig:option:`CONFIG_EXCEPTIONS`    | :kconfig:option:`CONFIG_CPP_EXCEPTIONS`        |
     +----------------------------------------+------------------------------------------------+
     | :kconfig:option:`CONFIG_RTTI`          | :kconfig:option:`CONFIG_CPP_RTTI`              |
     +----------------------------------------+------------------------------------------------+
     | :kconfig:option:`CONFIG_LIB_CPLUSPLUS` | :kconfig:option:`CONFIG_LIBCPP_IMPLEMENTATION` |
     +----------------------------------------+------------------------------------------------+

* MCUmgr subsystem, specifically the SMP transport API, is dropping `zephyr_`
  prefix, deprecating prefixed functions and callback type definitions with the
  prefix and replacing them with with prefix-less variants.
  The :c:struct:`zephyr_smp_transport` type, representing transport object,
  is now replaced with :c:struct:`smp_transport`, and the later one is used,
  instead of the former one, by all prefix-less functions.

  Deprecated functions and their replacements:

  .. table::
     :align: center

     +-------------------------------------+---------------------------------------+
     | Deprecated                          | Drop in replacement                   |
     +=====================================+=======================================+
     | :c:func:`zephyr_smp_transport_init` | :c:func:`smp_transport_init`          |
     +-------------------------------------+---------------------------------------+
     | :c:func:`zephyr_smp_rx_req`         | :c:func:`smp_rx_req`                  |
     +-------------------------------------+---------------------------------------+
     | :c:func:`zephyr_smp_alloc_rsp`      | :c:func:`smp_alloc_rsp`               |
     +-------------------------------------+---------------------------------------+
     | :c:func:`zephyr_smp_free_buf`       | :c:func:`smp_free_buf`                |
     +-------------------------------------+---------------------------------------+

  Deprecated callback types and their replacements:

  .. table::
     :align: center

     +---------------------------------------------+---------------------------------------+
     | Deprecated                                  | Drop in replacement                   |
     +=============================================+=======================================+
     | :c:func:`zephyr_smp_transport_out_fn`       | :c:func:`smp_transport_out_fn`        |
     +---------------------------------------------+---------------------------------------+
     | :c:func:`zephyr_smp_transport_get_mtu_fn`   | :c:func:`smp_transport_get_mtu_fn`    |
     +---------------------------------------------+---------------------------------------+
     | :c:func:`zephyr_smp_transport_ud_copy_fn`   | :c:func:`smp_transport_ud_copy_fn`    |
     +---------------------------------------------+---------------------------------------+
     | :c:func:`zephyr_smp_transport_ud_free_fn`   | :c:func:`smp_transport_ud_free_fn`    |
     +---------------------------------------------+---------------------------------------+

  NOTE: Only functions are marked as ``__deprecated``, type definitions are not.

* STM32 Ethernet Mac address Kconfig related symbols (:kconfig:option:`CONFIG_ETH_STM32_HAL_RANDOM_MAC`,
  :kconfig:option:`CONFIG_ETH_STM32_HAL_MAC4`, ...) have been deprecated in favor
  of the use of zephyr generic device tree ``local-mac-address`` and ``zephyr,random-mac-address``
  properties.

* STM32 RTC source clock should now be configured using devicetree.
  Related Kconfig :kconfig:option:`CONFIG_COUNTER_RTC_STM32_CLOCK_LSI` and
  :kconfig:option:`CONFIG_COUNTER_RTC_STM32_CLOCK_LSE` options are now
  deprecated.

* STM32 Interrupt controller Kconfig symbols such as :kconfig:option:`CONFIG_EXTI_STM32_EXTI0_IRQ_PRI`
  are removed. Related IRQ prioritues should now be configured in device tree.

* File backend for settings APIs and Kconfig options were deprecated:

  :c:func:`settings_mount_fs_backend` in favor of :c:func:`settings_mount_file_backend`

  :kconfig:option:`CONFIG_SETTINGS_FS` in favor of :kconfig:option:`CONFIG_SETTINGS_FILE`

  :kconfig:option:`CONFIG_SETTINGS_FS_DIR` in favor of creating all parent
  directories from :kconfig:option:`CONFIG_SETTINGS_FILE_PATH`

  :kconfig:option:`CONFIG_SETTINGS_FS_FILE` in favor of :kconfig:option:`CONFIG_SETTINGS_FILE_PATH`

  :kconfig:option:`CONFIG_SETTINGS_FS_MAX_LINES` in favor of :kconfig:option:`CONFIG_SETTINGS_FILE_MAX_LINES`

* PCIe APIs :c:func:`pcie_probe` and :c:func:`pcie_bdf_lookup` have been
  deprecated in favor of a centralized scan of available PCIe devices.

* SPI DT :c:func:`spi_is_ready` function has been deprecated in favor of :c:func:`spi_is_ready_dt`.

* LwM2M APIs using string references as LwM2M paths has been deprecated in favor of functions
  using :c:struct:`lwm2m_path_obj` instead.

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 :ref:`migration guide <mcumgr_cb_migration>`

* :c:func:`net_pkt_get_frag`, :c:func:`net_pkt_get_reserve_tx_data` and
  :c:func:`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 :kconfig:option:`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
========================

Kernel
******

Architectures
*************

* ARM

* ARM

* ARM64

  * Implemented ASID support for ARM64 MMU

* RISC-V

* Xtensa

Bluetooth
*********

* Audio

* Direction Finding

* Host

  * 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.

* Mesh

  * Change default advertiser to be extended advertiser.

* Controller

* HCI Driver

Boards & SoC Support
********************

* Added support for these SoC series:

* Removed support for these SoC series:

* Made these changes in other SoC series:

* Changes for ARC boards:

* Added support for these ARM boards:

* Added support for these ARM64 boards:

  * i.MX93 (Cortex-A) EVK board
  * Khadas Edge-V board
  * QEMU Virt KVM

* Removed support for these ARM boards:

* Removed support for these X86 boards:

* Added support for these RISC-V boards:

* Added support for these Xtensa boards:

* Removed support for these Xtensa boards:

* Made these changes in ARM boards:

  * 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.

* Made these changes in other boards:

* Added support for these following shields:

  * nPM6001 EK
  * nPM1100 EK

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.

* 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

* 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

* Counter

  * STM32 RTC based counter should now be configured using device tree.

* Crypto

* DAC

* DFU

  * Remove :c:macro:`BOOT_TRAILER_IMG_STATUS_OFFS` in favor a two new functions;
    :c:func:`boot_get_area_trailer_status_offset` and :c:func:`boot_get_trailer_status_offset`

* Disk

* Display

* DMA

* EEPROM

* Entropy

* ESPI

* 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.

* 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).

* GPIO

  * Added driver for nPM6001 PMIC GPIOs

* I2C

* I2S

* I3C

* IEEE 802.15.4

* Interrupt Controller

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

* IPM

* KSCAN

* LED

* MBOX

* MEMC

* PCIE

* PECI

* Pin control

  * Common pin control properties are now defined at root level in a single
    file: :zephyr_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, sinc all in-tree drivers have been updated.

* PWM

* Power domain

* 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

* SDHC

* Sensor

* Serial

* SPI

* Timer

* 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.

* W1

* Watchdog

  * Added driver for nPM6001 PMIC Watchdog.

* WiFi

Networking
**********

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 :kconfig:option:`CONFIG_NET_IPV4_FRAGMENT`.

USB
***

Devicetree
**********

* Bindings

  * New:

    * :dtcompatible:`zephyr,flash-disk`

    * STM32 SoCs:

      * :dtcompatible: `st,stm32-lse-clock`: new ``lse-bypass`` property
      * :dtcompatible: `st,stm32-ethernet`: now allows ``local-mac-address`` and
         ``zephyr,random-mac-address`` properties.

Libraries / Subsystems
**********************

* 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``.
  * :kconfig:option:`CONFIG_CPLUSPLUS` has been renamed to
    :kconfig:option:`CONFIG_CPP`.
  * :kconfig:option:`CONFIG_EXCEPTIONS` has been renamed to
    :kconfig:option:`CONFIG_CPP_EXCEPTIONS`.
  * :kconfig:option:`CONFIG_RTTI` has been renamed to
    :kconfig:option:`CONFIG_CPP_RTTI`.
  * :kconfig:option:`CONFIG_LIB_CPLUSPLUS` is deprecated. A toolchain-specific
    C++ standard library Kconfig option from
    :kconfig:option:`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
    :kconfig:option:`CONFIG_REQUIRES_FULL_LIBC`, which automatically selects
    a compatible C++ standard library.

* Cache

  * Introduced new Cache API
  * ``CONFIG_HAS_ARCH_CACHE`` has been renamed to
    :kconfig:option:`CONFIG_ARCH_CACHE`
  * ``CONFIG_HAS_EXTERNAL_CACHE`` has been renamed to
    :kconfig:option:`CONFIG_EXTERNAL_CACHE`

* 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 :ref:`fcb_api` by enabling the
    Kconfig option :kconfig:option:`CONFIG_FCB_ALLOW_FIXED_ENDMARKER`
    and setting the `FCB_FLAGS_CRC_DISABLED` flag in the :c:struct:`fcb` struct.

* IPC

  * Added :c:func:`ipc_rpmsg_deinit`, :c:func:`ipc_service_close_instance` and
    :c:func:`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.

* 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 (:ref:`mcumgr_callbacks`).
  * MCUmgr subsystem directory structure has been flattened and contents of the
    lib subdirectory has been redistributed into following directories:

    .. table::
       :align: center

       +----------------+-------------------------------------------+
       | Subdirectory   | MCUmgr area                               |
       +================+===========================================+
       | mgmt           | MCUmgr management functions, group        |
       |                | registration, and so on;                  |
       +----------------+-------------------------------------------+
       | smp            | Simple Management Protocol processing;    |
       +----------------+-------------------------------------------+
       | transport      | Transport support and transport API;      |
       +----------------+-------------------------------------------+
       | grp            | Command groups, formerly lib/cmd;         |
       |                | each group, which has Zephyr built in     |
       |                | support has its own directory here;       |
       +----------------+-------------------------------------------+
       | util           | 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 :ref:`mcumgr_os_application_info` for details.

  * MCUMgr :kconfig:option:`CONFIG_APP_LINK_WITH_MCUMGR` has been removed as
    it has not been doing anything.

  * MCUmgr Kconfig option names have been standardised. Script
    :zephyr_file:`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:

    .. table::
       :align: center

       +------------------------------------------------+-------------------------------------------------------+
       | Old Kconfig option name                        | New Kconfig option name                               |
       +================================================+=======================================================+
       | MCUMGR_SMP_WORKQUEUE_STACK_SIZE                | MCUMGR_TRANSPORT_WORKQUEUE_STACK_SIZE                 |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_WORKQUEUE_THREAD_PRIO               | MCUMGR_TRANSPORT_WORKQUEUE_THREAD_PRIO                |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MAX_MAIN_MAP_ENTRIES                      | MCUMGR_SMP_CBOR_MAX_MAIN_MAP_ENTRIES                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MIN_DECODING_LEVELS                       | MCUMGR_SMP_CBOR_MIN_DECODING_LEVELS                   |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MIN_DECODING_LEVEL_1                      | MCUMGR_SMP_CBOR_MIN_DECODING_LEVEL_1                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MIN_DECODING_LEVEL_2                      | MCUMGR_SMP_CBOR_MIN_DECODING_LEVEL_2                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MIN_DECODING_LEVEL_3                      | MCUMGR_SMP_CBOR_MIN_DECODING_LEVEL_3                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MIN_DECODING_LEVEL_4                      | MCUMGR_SMP_CBOR_MIN_DECODING_LEVEL_4                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MIN_DECODING_LEVEL_5                      | MCUMGR_SMP_CBOR_MIN_DECODING_LEVEL_5                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_MAX_DECODING_LEVELS                       | MCUMGR_SMP_CBOR_MAX_DECODING_LEVELS                   |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_CMD_FS_MGMT                             | MCUMGR_GRP_FS                                         |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_MAX_FILE_SIZE_64KB                     | MCUMGR_GRP_FS_MAX_FILE_SIZE_64KB                      |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_MAX_FILE_SIZE_4GB                      | MCUMGR_GRP_FS_MAX_FILE_SIZE_4GB                       |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_MAX_OFFSET_LEN                         | MCUMGR_GRP_FS_MAX_OFFSET_LEN                          |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_DL_CHUNK_SIZE_LIMIT                    | MCUMGR_GRP_FS_DL_CHUNK_SIZE_LIMIT                     |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_DL_CHUNK_SIZE                          | MCUMGR_GRP_FS_DL_CHUNK_SIZE                           |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_FILE_STATUS                            | MCUMGR_GRP_FS_FILE_STATUS                             |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_CHECKSUM_HASH                          | MCUMGR_GRP_FS_CHECKSUM_HASH                           |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_CHECKSUM_HASH_CHUNK_SIZE               | MCUMGR_GRP_FS_CHECKSUM_HASH_CHUNK_SIZE                |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_CHECKSUM_IEEE_CRC32                    | MCUMGR_GRP_FS_CHECKSUM_IEEE_CRC32                     |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_HASH_SHA256                            | MCUMGR_GRP_FS_HASH_SHA256                             |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_FILE_ACCESS_HOOK                       | MCUMGR_GRP_FS_FILE_ACCESS_HOOK                        |
       +------------------------------------------------+-------------------------------------------------------+
       | FS_MGMT_PATH_SIZE                              | MCUMGR_GRP_FS_PATH_LEN                                |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_CMD_IMG_MGMT                            | MCUMGR_GRP_IMG                                        |
       +------------------------------------------------+-------------------------------------------------------+
       | IMG_MGMT_USE_HEAP_FOR_FLASH_IMG_CONTEXT        | MCUMGR_GRP_IMG_USE_HEAP_FOR_FLASH_IMG_CONTEXT         |
       +------------------------------------------------+-------------------------------------------------------+
       | IMG_MGMT_UPDATABLE_IMAGE_NUMBER                | MCUMGR_GRP_IMG_UPDATABLE_IMAGE_NUMBER                 |
       +------------------------------------------------+-------------------------------------------------------+
       | IMG_MGMT_VERBOSE_ERR                           | MCUMGR_GRP_IMG_VERBOSE_ERR                            |
       +------------------------------------------------+-------------------------------------------------------+
       | IMG_MGMT_DUMMY_HDR                             | MCUMGR_GRP_IMG_DUMMY_HDR                              |
       +------------------------------------------------+-------------------------------------------------------+
       | IMG_MGMT_DIRECT_IMAGE_UPLOAD                   | MCUMGR_GRP_IMG_DIRECT_UPLOAD                          |
       +------------------------------------------------+-------------------------------------------------------+
       | IMG_MGMT_REJECT_DIRECT_XIP_MISMATCHED_SLOT     | MCUMGR_GRP_IMG_REJECT_DIRECT_XIP_MISMATCHED_SLOT      |
       +------------------------------------------------+-------------------------------------------------------+
       | IMG_MGMT_FRUGAL_LIST                           | MCUMGR_GRP_IMG_FRUGAL_LIST                            |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_CMD_OS_MGMT                             | MCUMGR_GRP_OS                                         |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_GRP_OS_OS_RESET_HOOK                    | MCUMGR_GRP_OS_RESET_HOOK                              |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_RESET_MS                               | MCUMGR_GRP_OS_RESET_MS                                |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_TASKSTAT                               | MCUMGR_GRP_OS_TASKSTAT                                |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_TASKSTAT_ONLY_SUPPORTED_STATS          | MCUMGR_GRP_OS_TASKSTAT_ONLY_SUPPORTED_STATS           |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_TASKSTAT_MAX_NUM_THREADS               | MCUMGR_GRP_OS_TASKSTAT_MAX_NUM_THREADS                |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_TASKSTAT_THREAD_NAME_LEN               | MCUMGR_GRP_OS_TASKSTAT_THREAD_NAME_LEN                |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_TASKSTAT_SIGNED_PRIORITY               | MCUMGR_GRP_OS_TASKSTAT_SIGNED_PRIORITY                |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_TASKSTAT_STACK_INFO                    | MCUMGR_GRP_OS_TASKSTAT_STACK_INFO                     |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_ECHO                                   | MCUMGR_GRP_OS_ECHO                                    |
       +------------------------------------------------+-------------------------------------------------------+
       | OS_MGMT_MCUMGR_PARAMS                          | MCUMGR_GRP_OS_MCUMGR_PARAMS                           |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_CMD_SHELL_MGMT                          | MCUMGR_GRP_SHELL                                      |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_CMD_SHELL_MGMT_LEGACY_RC_RETURN_CODE    | MCUMGR_GRP_SHELL_LEGACY_RC_RETURN_CODE                |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_CMD_STAT_MGMT                           | MCUMGR_GRP_STAT                                       |
       +------------------------------------------------+-------------------------------------------------------+
       | STAT_MGMT_MAX_NAME_LEN                         | MCUMGR_GRP_STAT_MAX_NAME_LEN                          |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_GRP_ZEPHYR_BASIC                        | MCUMGR_GRP_ZBASIC                                     |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_GRP_BASIC_CMD_STORAGE_ERASE             | MCUMGR_GRP_ZBASIC_STORAGE_ERASE                       |
       +------------------------------------------------+-------------------------------------------------------+
       | MGMT_VERBOSE_ERR_RESPONSE                      | MCUMGR_SMP_VERBOSE_ERR_RESPONSE                       |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_REASSEMBLY                          | MCUMGR_TRANSPORT_REASSEMBLY                           |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_BUF_COUNT                               | MCUMGR_TRANSPORT_NETBUF_COUNT                         |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_BUF_SIZE                                | MCUMGR_TRANSPORT_NETBUF_SIZE                          |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_BUF_USER_DATA_SIZE                      | MCUMGR_TRANSPORT_NETBUF_USER_DATA_SIZE                |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT                                  | MCUMGR_TRANSPORT_BT                                   |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_REASSEMBLY_BT                       | MCUMGR_TRANSPORT_BT_REASSEMBLY                        |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_REASSEMBLY_UNIT_TESTS               | MCUMGR_TRANSPORT_REASSEMBLY_UNIT_TESTS                |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_AUTHEN                           | MCUMGR_TRANSPORT_BT_AUTHEN                            |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_CONN_PARAM_CONTROL               | MCUMGR_TRANSPORT_BT_CONN_PARAM_CONTROL                |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_CONN_PARAM_CONTROL_MIN_INT       | MCUMGR_TRANSPORT_BT_CONN_PARAM_CONTROL_MIN_INT        |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_CONN_PARAM_CONTROL_MAX_INT       | MCUMGR_TRANSPORT_BT_CONN_PARAM_CONTROL_MAX_INT        |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_CONN_PARAM_CONTROL_LATENCY       | MCUMGR_TRANSPORT_BT_CONN_PARAM_CONTROL_LATENCY        |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_CONN_PARAM_CONTROL_TIMEOUT       | MCUMGR_TRANSPORT_BT_CONN_PARAM_CONTROL_TIMEOUT        |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_CONN_PARAM_CONTROL_RESTORE_TIME  | MCUMGR_TRANSPORT_BT_CONN_PARAM_CONTROL_RESTORE_TIME   |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_BT_CONN_PARAM_CONTROL_RETRY_TIME    | MCUMGR_TRANSPORT_BT_CONN_PARAM_CONTROL_RETRY_TIME     |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_DUMMY                               | MCUMGR_TRANSPORT_DUMMY                                |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_DUMMY_RX_BUF_SIZE                   | MCUMGR_TRANSPORT_DUMMY_RX_BUF_SIZE                    |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_SHELL                               | MCUMGR_TRANSPORT_SHELL                                |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_SHELL_MTU                           | MCUMGR_TRANSPORT_SHELL_MTU                            |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_SHELL_RX_BUF_COUNT                  | MCUMGR_TRANSPORT_SHELL_RX_BUF_COUNT                   |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UART                                | MCUMGR_TRANSPORT_UART                                 |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UART_ASYNC                          | MCUMGR_TRANSPORT_UART_ASYNC                           |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UART_ASYNC_BUFS                     | MCUMGR_TRANSPORT_UART_ASYNC_BUFS                      |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UART_ASYNC_BUF_SIZE                 | MCUMGR_TRANSPORT_UART_ASYNC_BUF_SIZE                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UART_MTU                            | MCUMGR_TRANSPORT_UART_MTU                             |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UDP                                 | MCUMGR_TRANSPORT_UDP                                  |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UDP_IPV4                            | MCUMGR_TRANSPORT_UDP_IPV4                             |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UDP_IPV6                            | MCUMGR_TRANSPORT_UDP_IPV6                             |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UDP_PORT                            | MCUMGR_TRANSPORT_UDP_PORT                             |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UDP_STACK_SIZE                      | MCUMGR_TRANSPORT_UDP_STACK_SIZE                       |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UDP_THREAD_PRIO                     | MCUMGR_TRANSPORT_UDP_THREAD_PRIO                      |
       +------------------------------------------------+-------------------------------------------------------+
       | MCUMGR_SMP_UDP_MTU                             | MCUMGR_TRANSPORT_UDP_MTU                              |
       +------------------------------------------------+-------------------------------------------------------+

  * 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
    :kconfig:option:`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: :kconfig:option:`CONFIG_MCUMGR_GRP_FS_LOG_LEVEL`,
    :kconfig:option:`CONFIG_MCUMGR_GRP_IMG_LOG_LEVEL`,
    :kconfig:option:`CONFIG_MCUMGR_GRP_OS_LOG_LEVEL`,
    :kconfig:option:`CONFIG_MCUMGR_GRP_SHELL_LOG_LEVEL`,
    :kconfig:option:`CONFIG_MCUMGR_GRP_STAT_LOG_LEVEL` and
    :kconfig:option:`CONFIG_MCUMGR_GRP_ZBASIC_LOG_LEVEL`.

  * MCUmgr img_mgmt has a new field which is sent in the final packet (if
    :kconfig:option:`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
    :kconfig:option:`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,
    :kconfig:option:`CONFIG_LOG_PRINTK` should be enabled to include this fix.

* LwM2M

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

* Settings

  * Replaced all :c:func:`k_panic` invocations within settings backend
    initialization with returning / propagating error codes.

* Utilities

  * Added the linear range API to map values in a linear range to a range index
    :zephyr_file:`include/zephyr/sys/linear_range.h`.

HALs
****

MCUboot
*******

Storage
*******

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

Trusted Firmware-M
******************

zcbor
*****

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 :c:macro:`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

Documentation
*************

* Upgraded to Doxygen 1.9.6.
* It is now possible to link to Kconfig search results.

Tests and Samples
*****************

Issue Related Items
*******************

Known Issues
============

Addressed issues
================