:orphan:

.. _zephyr_3.4:

Zephyr 3.4.0 (Working Draft)
############################

We are pleased to announce the release of Zephyr version 3.4.0.

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
=======================

* Any applications using the mcuboot image manager
  (:kconfig:option:`CONFIG_MCUBOOT_IMG_MANAGER`) will now need to also select
  :kconfig:option:`CONFIG_FLASH_MAP` and :kconfig:option:`CONFIG_STREAM_FLASH`,
  this prevents a cmake dependency loop if the image manager Kconfig is enabled
  manually without also manually enabling the other options.

* Including hawkbit in an application now requires additional Kconfig options
  to be selected, previously these options would have been selected
  automatically but have changed from ``select`` options in Kconfig files to
  ``depends on``:

   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NVS`                     |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_FLASH`                   |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_FLASH_MAP`               |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_STREAM_FLASH`            |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_REBOOT`                  |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_HWINFO`                  |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NET_TCP`                 |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NET_SOCKETS`             |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_IMG_MANAGER`             |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NETWORKING`              |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_HTTP_CLIENT`             |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_DNS_RESOLVER`            |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_JSON_LIBRARY`            |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NET_SOCKETS_POSIX_NAMES` |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_BOOTLOADER_MCUBOOT`      |
   +--------------------------------------------------+

* Including updatehub in an application now requires additional Kconfig options
  to be selected, previously these options would have been selected
  automatically but have changed from ``select`` options in Kconfig files to
  ``depends on``:

   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_FLASH`                   |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_STREAM_FLASH`            |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_FLASH_MAP`               |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_REBOOT`                  |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_MCUBOOT_IMG_MANAGER`     |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_IMG_MANAGER`             |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_IMG_ENABLE_IMAGE_CHECK`  |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_BOOTLOADER_MCUBOOT`      |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_MPU_ALLOW_FLASH_WRITE`   |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NETWORKING`              |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NET_UDP`                 |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NET_SOCKETS`             |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_NET_SOCKETS_POSIX_NAMES` |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_COAP`                    |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_DNS_RESOLVER`            |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_JSON_LIBRARY`            |
   +--------------------------------------------------+
   | :kconfig:option:`CONFIG_HWINFO`                  |
   +--------------------------------------------------+

* The sensor driver API clarified :c:func:`sensor_trigger_set` to state that
  the user-allocated sensor trigger will be stored by the driver as a pointer,
  rather than a copy, and passed back to the handler. This enables the handler
  to use :c:macro:`CONTAINER_OF` to retrieve a context pointer when the trigger
  is embedded in a larger struct and requires that the trigger is not allocated
  on the stack. Applications that allocate a sensor trigger on the stack need
  to be updated.

* Converted few drivers to the :ref:`input` subsystem.

  * ``gpio_keys``: moved out of ``gpio``, replaced the custom API to use input
    events instead, the :dtcompatible:`zephyr,gpio-keys` binding is unchanged
    but now requires ``zephyr,code`` to be set.
  * ``ft5336``: moved from :ref:`kscan_api` to :ref:`input`, renamed the Kconfig
    options from ``CONFIG_KSCAN_FT5336``, ``CONFIG_KSCAN_FT5336_PERIOD`` and
    ``KSCAN_FT5336_INTERRUPT`` to :kconfig:option:`CONFIG_INPUT_FT5336`,
    :kconfig:option:`CONFIG_INPUT_FT5336_PERIOD` and
    :kconfig:option:`CONFIG_INPUT_FT5336_INTERRUPT`.
  * ``kscan_sdl``: moved from :ref:`kscan_api` to :ref:`input`, renamed the Kconfig
    option from ``KSCAN_SDL`` to :kconfig:option:`CONFIG_INPUT_SDL_TOUCH` and the
    compatible from ``zephyr,sdl-kscan`` to
    :dtcompatible:`zephyr,input-sdl-touch`.
  * ``nuvoton,npcx-kscan`` moved to :ref:`input`, renamed the Kconfig option
    names from ``KSCAN_NPCX_...`` to ``INPUT_NPCX_KBD...`` and the compatible
    from ``nuvoton,npcx-kscan`` to :dtcompatible:`nuvoton,npcx-kbd`.
  * Touchscreen drivers converted to use the input APIs can use the
    :dtcompatible:`zephyr,kscan-input` driver to maintain Kscan compatilibity.

* The declaration of :c:func:`main` has been changed from ``void
  main(void)`` to ``int main(void)``. The main function is required to
  return the value zero. All other return values are reserved. This aligns
  Zephyr with the C and C++ language specification requirements for
  "hosted" environments, avoiding compiler warnings and errors. These
  compiler messages are generated when applications are built in "hosted"
  mode (which means without the ``-ffreestanding`` compiler flag). As the
  ``-ffreestanding`` flag is currently enabled unless the application is
  using picolibc, only applications using picolibc will be affected by this
  change at this time.

* The following network interface APIs now take additional,
  ``struct net_if * iface`` parameter:

  * :c:func:`net_if_ipv4_maddr_join`
  * :c:func:`net_if_ipv4_maddr_leave`
  * :c:func:`net_if_ipv6_maddr_join`
  * :c:func:`net_if_ipv6_maddr_leave`

* MCUmgr transports now need to set up the struct before registering it by
  setting the function pointers to the function handlers, these have been
  moved to a ``functions`` struct object of type
  :c:struct:`smp_transport_api_t`. Because of these changes, the legacy
  transport registration function and object are no longer available. The
  registration function now returns a value which is 0 for success or a
  negative error code if an error occurred.

* Added a new flag :c:struct:`dac_channel_cfg` ``buffered`` for DAC channels in
  :c:struct:`dac_channel_cfg` to allow the configuration of the output buffer.
  The actual interpretation of this depends on the hardware and is so far only
  implemented for the STM32 DAC driver. Implicitly for this driver this changes
  the default from being buffered to unbuffered.

* MCUmgr fs_mgmt group's file access hook is now called for all fs_mgmt group
  functions (adding support for file status and file hash/checksum). In
  addition, if the file access state is not lost, it will now only be called
  once for the file access instead of each time a command is received.
  Note that the structure for the notification has changed, the ``upload`` bool
  has been replaced with an enum to indicate what function is used, see
  :c:struct:`fs_mgmt_file_access` for the new structure definition.

* Iterable sections API is now available at
  :zephyr_file:`zephyr/sys/iterable_sections.h`. LD linker snippets are
  available at :zephyr_file:`zephyr/linker/iterable_sections.h`.

* Cache API functions are now fully inlined by compilers.

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

* Pinmux API has been removed. Pin control needs to be used as its replacement,
  refer to :ref:`pinctrl-guide` for more details.

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

* Configuring applications with ``prj_<board>.conf`` files has been deprecated,
  this should be replaced by using a prj.conf with the common configuration and
  board-specific configuration in board Kconfig fragments in the ``boards``
  folder of the application.

* On nRF51 and nRF52-based boards, the behaviour of the reset reason being
  provided to :c:func:`sys_reboot` and being set in the GPREGRET register has
  been dropped. This function will now just reboot the device without changing
  the register contents. The new method for setting this register uses the boot
  mode feature of the retention subsystem, see the
  :ref:`boot mode API <boot_mode_api>` for details. To restore the deprecated
  functionality, enable
  :kconfig:option:`CONFIG_NRF_STORE_REBOOT_TYPE_GPREGRET`.

Stable API changes in this release
==================================

* Removed `bt_set_oob_data_flag` and replaced it with two new API calls:
  * :c:func:`bt_le_oob_set_sc_flag` for setting/clearing OOB flag in SC pairing
  * :c:func:`bt_le_oob_set_legacy_flag` for setting/clearing OOB flag in legacy paring

* :c:macro:`SYS_INIT` callback no longer requires a :c:struct:`device` argument.
  The new callback signature is ``int f(void)``. A utility script to
  automatically migrate existing projects can be found in
  :zephyr_file:`scripts/utils/migrate_sys_init.py`.

* Changed :c:struct:`spi_config` ``cs`` (:c:struct:`spi_cs_control`) from
  pointer to struct member. This allows using the existing SPI dt-spec macros in
  C++. SPI controller drivers doing ``NULL`` checks on the ``cs`` field to check
  if CS is GPIO-based or not, must now use :c:func:`spi_cs_is_gpio` or
  :c:func:`spi_cs_is_gpio_dt` calls.

New APIs in this release
========================

* Introduced :c:func:`flash_ex_op` function. This allows to perform extra
  operations on flash devices, defined by Zephyr Flash API or by vendor specific
  header files. Support for extra operations is enabled by
  :kconfig:option:`CONFIG_FLASH_EX_OP_ENABLED` which depends on
  :kconfig:option:`CONFIG_FLASH_HAS_EX_OP` selected by driver.

* Introduced :ref:`rtc_api` API which adds experimental support for real-time clock
  devices. These devices previously used the :ref:`counter_api` API combined with
  conversion between unix-time and broken-down time. The new API adds the mandatory
  functions :c:func:`rtc_set_time` and :c:func:`rtc_get_time`, the optional functions
  :c:func:`rtc_alarm_get_supported_fields`, :c:func:`rtc_alarm_set_time`,
  :c:func:`rtc_alarm_get_time`, :c:func:`rtc_alarm_is_pending` and
  :c:func:`rtc_alarm_set_callback` are enabled with
  :kconfig:option:`CONFIG_RTC_ALARM`, the optional function
  :c:func:`rtc_update_set_callback` is enabled with
  :kconfig:option:`CONFIG_RTC_UPDATE`, and lastly, the optional functions
  :c:func:`rtc_set_calibration` and :c:func:`rtc_get_calibration` are enabled with
  :kconfig:option:`CONFIG_RTC_CALIBRATION`.

* Introduced :ref:`auxdisplay_api` for auxiliary (alphanumeric-based) displays.

* Introduced :ref:`barriers_api` for barrier operations.

Kernel
******

* Removed absolute symbols :c:macro:`___cpu_t_SIZEOF`,
  :c:macro:`_STRUCT_KERNEL_SIZE`, :c:macro:`K_THREAD_SIZEOF` and
  :c:macro:`_DEVICE_STRUCT_SIZEOF`

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

* ARC
  * Removed absolute symbols :c:macro:`___callee_saved_t_SIZEOF` and
  :c:macro:`_K_THREAD_NO_FLOAT_SIZEOF`

* ARM
  * Removed absolute symbols :c:macro:`___basic_sf_t_SIZEOF`,
  :c:macro:`_K_THREAD_NO_FLOAT_SIZEOF`, :c:macro:`___cpu_context_t_SIZEOF`
  and :c:macro:`___thread_stack_info_t_SIZEOF`

* ARM64
  * Removed absolute symbol :c:macro:`___callee_saved_t_SIZEOF`
  * Enabled FPU and FPU_SHARING for v8r aarch64
  * Fixed the STACK_INIT logic during the reset
  * Introduced and enabled safe exception stack
  * Fixed possible deadlock on SMP with FPU sharing
  * Added ISBs after SCTLR Modifications

* NIOS2
  * Removed absolute symbol :c:macro:`_K_THREAD_NO_FLOAT_SIZEOF`

* RISC-V

  * Added :kconfig:option:`CONFIG_PMP_NO_TOR`, :kconfig:option:`CONFIG_PMP_NO_NA4`, and
    :kconfig:option:`CONFIG_PMP_NO_NAPOT` to allow disabling unsupported PMP range modes.
  * Removed unused symbols: :c:macro:`_thread_offset_to_tp`,
    :c:macro:`_thread_offset_to_priv_stack_start`, :c:macro:`_thread_offset_to_user_sp`.
  * Added support for setting PMP granularity with :kconfig:option:`CONFIG_PMP_GRANULARITY`.
  * Switched from accessing CSRs from inline assembly to using the :c:func:`csr_read` helper
    function.
  * Enabled single-threading support.

* SPARC
  * Removed absolute symbol :c:macro:`_K_THREAD_NO_FLOAT_SIZEOF`

* X86

* Xtensa

Bluetooth
*********

* Audio

* Direction Finding

* Host

* Mesh

  * Added experimental support for Mesh Protocol d1.1r18 specification.
  * Added experimental support for Mesh Binary Large Object Transfer Model d1.0r04_PRr00 specification.
  * Added experimental support for Mesh Device Firmware Update Model d1.0r04_PRr00 specification.

* 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:

* Added support for these ARC boards:

* Added support for these ARM boards:

  * Seeed Studio Wio Terminal

* Added support for these ARM64 boards:

  * PHYTEC phyCORE-AM62x A53
  * MIMX93 EVK A53 (SOF)

* Added support for these RISC-V boards:

* Added support for these X86 boards:

* Added support for these Xtensa boards:

* Made these changes for ARC boards:

* Made these changes for ARM boards:

  * Changed the default board revision to 0.14.0 for the Nordic boards
    ``nrf9160dk_nrf9160`` and ``nrf9160dk_nrf52840``. To build for an
    older revision of the nRF9160 DK without external flash, specify that
    older board revision when building.
  * ``nrf9160dk_nrf52840``: Enabled external_flash_pins_routing switch by default.
  * ``nrf9160dk_nrf9160``: Changed the order of buttons and switches on the GPIO
    expander to match the order when using GPIO directly on the nRF9160 SoC.

* Made these changes for ARM64 boards:

  * FVP revc_2xaemv8a / aemv8r: Added ethernet, PHY and MDIO nodes

* Made these changes for RISC-V boards:

* Made these changes for X86 boards:

* Made these changes for Xtensa boards:

* Removed support for these ARC boards:

* Removed support for these ARM boards:

* Removed support for these RISC-V boards:

  * BeagleV Starlight JH7100

* Removed support for these X86 boards:

* Removed support for these Xtensa boards:

* Made these changes in other boards:

* Added support for these following shields:

Build system and infrastructure
*******************************

* Fixed an issue whereby older versions of the Zephyr SDK toolchain were used
  instead of the latest compatible version.

* Fixed an issue whereby building an application with sysbuild and specifying
  mcuboot's verification to be checksum only did not build a bootable image.

* Fixed an issue whereby if no prj.conf file was present then board
  configuration files would not be included by emitting a fatal error. As a
  result, prj.conf files are now mandatory in projects.

* Introduced support for extending/replacing the signing mechanism in zephyr,
  see :ref:`West extending signing <west-extending-signing>` for further
  details.

* Fixed an issue whereby when using ``*_ROOT`` variables with Sysbuild, these
  were lost for images.

* Enhanced ``zephyr_get`` CMake helper function to optionally support merging
  of scoped variables into a list.

* Added a new CMake helper function for setting/updating sysbuild CMake cache
  variables: ``sysbuild_cache_set``.

* Enhanced ``zephyr_get`` CMake helper function to lookup multiple variables
  and return the result in a variable of different name.

* Introduced ``EXTRA_CONF_FILE``, ``EXTRA_DTC_OVERLAY_FILE``, and
  ``EXTRA_ZEPHYR_MODULES`` for better naming consistency and uniform behavior
  for applying extra build settings in addition to Zephyr automatic build
  setting lookup.
  ``EXTRA_CONF_FILE`` replaces ``OVERLAY_CONFIG``.
  ``EXTRA_ZEPHYR_MODULES`` replaces ``ZEPHYR_EXTRA_MODULES``.
  ``EXTRA_DTC_OVERLAY_FILE`` is new, see
  :ref:`Set devicetree overlays <set-devicetree-overlays>` for further details.

* Twister now supports ``gtest`` harness for running tests written in gTest.

* Added an option to validate device initialization priorities at build time.
  To use it, enable :kconfig:option:`CONFIG_CHECK_INIT_PRIORITIES`, see
  :ref:`check_init_priorities.py` for more details.

* Added a new option to disable tracking of macro expansion when compiling,
  :kconfig:option:`CONFIG_COMPILER_TRACK_MACRO_EXPANSION`. This option may be
  disabled to reduce compiler verbosity when errors occur during macro
  expansions, e.g. in device definition macros.

* Twister now supports loading test configurations from alternative root
  folder/s by using ``--alt-config-root``. When a test is found, Twister will
  check if a test configuration file exist in any of the alternative test
  configuration root folders. For example, given
  ``$test_root/tests/foo/testcase.yaml``, Twister will use
  ``$alt_config_root/tests/foo/testcase.yaml`` if it exists.

* Twister now uses native YAML lists for fields that were previously defined
  using space-separated strings. For example:

  .. code-block:: yaml

     platform_allow: foo bar

  can now be written as:

  .. code-block:: yaml

     platform_allow:
       - foo
       - bar

  This applies to the following properties:

    - ``arch_exclude``
    - ``arch_allow``
    - ``depends_on``
    - ``extra_args``
    - ``extra_sections``
    - ``platform_exclude``
    - ``platform_allow``
    - ``tags``
    - ``toolchain_exclude``
    - ``toolchain_allow``

  Note that the old behavior is kept as deprecated. The
  :zephyr_file:`scripts/utils/twister_to_list.py` script can be used to
  automatically migrate Twister configuration files.

Drivers and Sensors
*******************

* Device model

  * Devices that do not require an initialization routine can now pass ``NULL``
    to the ``DEVICE_*_DEFINE()`` macros.

* Auxiliary display

  * New auxiliary display (auxdisplay) peripheral has been added, this allows
    for interfacing with simple alphanumeric displays that do not feature
    graphic capabilities. This peripheral is marked as unstable.

  * HD44780 driver added.

  * Noritake Itron driver added.

  * Grove LCD driver added (ported from existing sample).

* ADC

 * MCUX LPADC driver now uses the channel parameter to select a software channel
   configuration buffer. Use ``zephyr,input-positive`` and
   ``zephyr,input-negative`` devicetree properties to select the hardware
   channel(s) to link a software channel configuration to.

 * MCUX LPADC driver ``voltage-ref`` and ``power-level`` devicetree properties
   were shifted to match the hardware as described in reference manual instead
   of matching the NXP SDK enum identifers.

* Battery-backed RAM

  * Added MCP7940N battery-backed RTC SRAM driver.

* CAN

* Clock control

* Counter

* Crypto

* DAC

* DFU

* Disk

* Display

* DMA

* EEPROM

  * Switched from :dtcompatible:`atmel,at24` to dedicated :dtcompatible:`zephyr,i2c-target-eeprom` for I2C EEPROM target driver.

* Entropy

* ESPI

* Ethernet

* Flash

  * Introduced new flash API call :c:func:`flash_ex_op` which calls
    :c:func:`ec_op` callback provided by a flash driver. This allows to perform
    extra operations on flash devices, defined by Zephyr Flash API or by vendor
    specific header files. :kconfig:option:`CONFIG_FLASH_HAS_EX_OP` should be
    selected by the driver to indicate that extra operations are supported.
    To enable extra operations user should select
    :kconfig:option:`CONFIG_FLASH_EX_OP_ENABLED`.
  * nrf_qspi_nor: Replaced custom API function ``nrf_qspi_nor_base_clock_div_force``
    with ``nrf_qspi_nor_xip_enable`` which apart from forcing the clock divider
    prevents the driver from deactivating the QSPI peripheral so that the XIP
    operation is actually possible.
  * flash_simulator: A memory region can now be used as the storage area for the
    flash simulator. Using the memory region allows the flash simulator to keep
    its contents over a device reboot.
  * spi_flash_at45: Fixed erase procedure to properly handle chips that have
    their initial sector split into two parts (usually marked as 0a and 0b).

* FPGA

* Fuel Gauge

* GPIO

  * Converted the ``gpio_keys`` driver to the input subsystem.

* hwinfo

* I2C

* I2S

* I3C

* IEEE 802.15.4

* Input

  * Introduced the :ref:`input` subsystem.

* Interrupt Controller

* IPM

* KSCAN

  * Added a :dtcompatible:`zephyr,kscan-input` input to kscan compatibility driver.
  * Converted the ``ft5336`` and ``kscan_sdl`` drivers to the input subsystem.

* LED

* MBOX

* MEMC

* PCIE

* PECI

* Retained memory

  * Retained memory (retained_mem) driver has been added with backends for
    Nordic nRF GPREGRET, and uninitialised RAM.

* Pin control

  * Added support for Infineon CAT1
  * Added support for TI K3
  * Added support for ARC emdsp

* PWM

* Power domain

* Regulators

  * The regulator API can now be built without thread-safe reference counting
    by using :kconfig:option:`CONFIG_REGULATOR_THREAD_SAFE_REFCNT`. This
    feature can be useful in applications that do not enable
    :kconfig:option:`CONFIG_MULTITHREADING`.
  * Added support for ADP5360 PMIC
  * Added support for nPM1300 PMIC
  * Added support for Raspberry Pi Pico core supply regulator

* Reset

* SDHC

* Sensor

* Serial

* SPI

* Timer

  * Support added for stopping Nordic nRF RTC system timer, which fixes an
    issue when booting applications built in prior version of Zephyr.

* USB

* W1

* Watchdog

* WiFi

Networking
**********
* Wi-Fi

  * TWT intervals are changed from milli-seconds to micro-seconds, interval variables are also renamed.

USB
***

Devicetree
**********

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

* File systems

  * Added :kconfig:option:`CONFIG_FS_FATFS_REENTRANT` to enable the FAT FS reentrant option.
  * With LittleFS as backend, :c:func:`fs_mount` return code was corrected to ``EFAULT`` when
    called with ``FS_MOUNT_FLAG_NO_FORMAT`` and the designated LittleFS area could not be
    mounted because it has not yet been mounted or it required reformatting.
  * The FAT FS initialization order has been updated to match LittleFS, fixing an issue where
    attempting to mount the disk in a global function caused FAT FS to fail due to not being registered beforehand.
    FAT FS is now initialized in POST_KERNEL.
  * Added :kconfig:option:`CONFIG_FS_LITTLEFS_FMP_DEV` to enable possibility of using LittleFS
    for block devices only, e.g. without Flash support. The option is set to 'y' by default in
    order to keep previous behaviour.

* IPC

  * :c:func:`ipc_service_close_instance` now only acts on bounded endpoints.
  * ICMSG: removed race condition during bonding.
  * ICMSG: removed internal API for clearing shared memory.
  * ICMSG: added mutual exclusion access to SHMEM.
  * Fixed CONFIG_OPENAMP_WITH_DCACHE.

* Management

  * Added optional input expiration to shell MCUmgr transport, this allows
    returning the shell to normal operation if a complete MCUmgr packet is not
    received in a specific duration. Can be enabled with
    :kconfig:option:`CONFIG_MCUMGR_TRANSPORT_SHELL_INPUT_TIMEOUT` and timeout
    set with
    :kconfig:option:`CONFIG_MCUMGR_TRANSPORT_SHELL_INPUT_TIMEOUT_TIME`.

  * MCUmgr fs_mgmt upload and download now caches the file handle to improve
    throughput when transferring data, the file is no longer opened and closed
    for each part of a transfer. In addition, new functionality has been added
    that will allow closing file handles of uploaded/downloaded files if they
    are idle for a period of time, the timeout is set with
    :kconfig:option:`MCUMGR_GRP_FS_FILE_AUTOMATIC_IDLE_CLOSE_TIME`. There is a
    new command that can be used to close open file handles which can be used
    after a file upload is complete to ensure that the file handle is closed
    correctly, allowing other transports or other parts of the application
    code to use it.

  * A new version of the SMP protocol used by MCUmgr has been introduced in the
    header, which is used to indicate the version of the protocol being used.
    This updated protocol allows returning much more detailed error responses
    per group, see the
    :ref:`MCUmgr SMP protocol specification <mcumgr_smp_protocol_specification>`
    for details.

  * MCUmgr has now been marked as a stable Zephyr API.

* Retention

  * Retention subsystem has been added which adds enhanced features over
    retained memory drivers allowing for partitioning, magic headers and
    checksum validation. See :ref:`retention API <retention_api>` for details.
    Support for the retention subsystem is experimental.

  * Boot mode retention module has been added which allows for setting/checking
    the boot mode of an application, initial support has also been added to
    MCUboot to allow for applications to use this as an entrance method for
    MCUboot serial recovery mode. See :ref:`boot mode API <boot_mode_api>` for
    details.

* RTIO

  * Added policy that every ``sqe`` will generate a ``cqe`` (previously an RTIO_SQE_TRANSACTION
    entry would only trigger a ``cqe`` on the last ``sqe`` in the transaction.

* Power management

  * Added a new policy event API that can be used to register expected events
    that will wake the system up in the future. This can be used to influence
    the system on which low power states can be used.

HALs
****

MCUboot
*******

* Relocated the MCUboot Kconfig options from the main ``Kconfig.zephyr`` file to
  a new ``modules/Kconfig.mcuboot`` module-specific file. This means that, for
  interactive Kconfig interfaces, the MCUboot options will now be located under
  ``Modules`` instead of under ``Boot Options``.

* Added :kconfig:option:`CONFIG_MCUBOOT_CMAKE_WEST_SIGN_PARAMS` that allows to pass arguments to
  west sign when invoked from cmake.

Storage
*******

* Added :kconfig:option:`CONFIG_FLASH_MAP_LABELS`, which will enable runtime access to the labels
  property of fixed partitions. This option is implied if kconfig:option:`CONFIG_FLASH_MAP_SHELL`
  is enabled. These labels will be displayed in a separate column when using the ``flash_map list``
  shell command.

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

zcbor
*****

Updated from 0.6.0 to 0.7.0.
Among other things, this update brings:

* C++ improvements
* float16 support
* Improved docs
* -Wall and -Wconversion compliance

Documentation
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Tests and Samples
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Issue Related Items
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Known Issues
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Addressed issues
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