Zephyr 4.0.0 (Working Draft)

We are pleased to announce the release of Zephyr version 4.0.0.

Major enhancements with this release include:

An overview of the changes required or recommended when migrating your application from Zephyr v3.7.0 to Zephyr v4.0.0 can be found in the separate migration guide.

The following sections provide detailed lists of changes by component.

Security Vulnerability Related

The following CVEs are addressed by this release:

More detailed information can be found in: https://docs.zephyrproject.org/latest/security/vulnerabilities.html

API Changes

• Removed deprecated arch-level CMSIS header files include/zephyr/arch/arm/cortex_a_r/cmsis.h and include/zephyr/arch/arm/cortex_m/cmsis.h. cmsis_core.h needs to be included now.

• Removed deprecated ceiling_fraction macro. DIV_ROUND_UP needs to be used now.

• Deprecated EARLY, APPLICATION and SMP init levels can no longer be used for devices.

Removed APIs in this release

• Macro K_THREAD_STACK_MEMBER, deprecated since v3.5.0, has been removed. Use K_KERNEL_STACK_MEMBER instead.

• CBPRINTF_PACKAGE_COPY_* macros, deprecated since Zephyr 3.5.0, have been removed.

Deprecated in this release

• Deprecated the net_buf_put() and net_buf_get() API functions in favor of k_fifo_put() and k_fifo_get().

Architectures

• ARC

• ARM

• ARM64

  • Added initial support for arch_stack_walk() that supports unwinding via esf only

• RISC-V

  • The stack traces upon fatal exception now prints the address of stack pointer (sp) or frame pointer (fp) depending on the build configuration.

  • When CONFIG_EXTRA_EXCEPTION_INFO is enabled, the exception stack frame (arch_esf) has an additional field csf that points to the callee-saved-registers upon an fatal error, which can be accessed in k_sys_fatal_error_handler() by esf->csf.

    • For SoCs that select RISCV_SOC_HAS_ISR_STACKING, the SOC_ISR_STACKING_ESF_DECLARE has to include the csf member, otherwise the build would fail.

• Xtensa

• x86

  • Added initial support for arch_stack_walk() that supports unwinding via esf only

Kernel

Bluetooth

• Audio

  • bt_tbs_client_register_cb() now supports multiple listeners and may now return an error.

• Host

  • Added API bt_gatt_get_uatt_mtu() to get current Unenhanced ATT MTU of a given connection (experimental).

• HCI Drivers

Boards & SoC Support

• Added support for these SoC series:

• Made these changes in other SoC series:

  • NXP S32Z270: Added support for the new silicon cut version 2.0. Note that the previous versions (1.0 and 1.1) are no longer supported.

• Added support for these boards:

• Made these board changes:

  • native_posix has been deprecated in favour of native_sim.

  • Support for Google Kukui EC board (google_kukui) has been dropped.

  • STM32: Deprecated MCO configuration via Kconfig in favour of setting it through devicetree. See samples/boards/stm32/mco sample.

• Added support for the following shields:

Build system and Infrastructure

• Added support for .elf files to the west flash command for jlink, pyocd and linkserver runners.

Documentation

• Added two new build commands, make html-live and make html-live-fast, that automatically locally host the generated documentation. They also automatically rebuild and rehost the documentation when changes to the input .rst files are detected on the filesystem.

Drivers and Sensors

• ADC

• Battery

• CAN

• Charger

• Clock control

• Counter

• DAC

• Disk

• Display

• Ethernet

  • LiteX: Renamed the compatible from litex,eth0 to litex,liteeth.

• Flash

• GNSS

• GPIO

• Hardware info

• I2C

• I2S

• I3C

• Input

• LED

  • lp5562: added enable-gpios property to describe the EN/VCC GPIO of the lp5562.

  • lp5569: added charge-pump-mode property to configure the charge pump of the lp5569.

  • lp5569: added enable-gpios property to describe the EN/PWM GPIO of the lp5569.

  • LED code samples have been consolidated under the samples/drivers/led directory.

• LED Strip

  • Updated ws2812 GPIO driver to support dynamic bus timings

• LoRa

• Mailbox

• MDIO

• MFD

• Modem

  • Added support for the U-Blox LARA-R6 modem.

  • Added support for setting the modem’s UART baudrate during init.

• MIPI-DBI

• MSPI

• Pin control

• PWM

• Regulators

• Reset

• RTC

• RTIO

• SDHC

• Sensors

  • The existing driver for the Microchip MCP9808 temperature sensor transformed and renamed to support all JEDEC JC 42.4 compatible temperature sensors. It now uses the jedec,jc-42.4-temp compatible string instead to the microchip,mcp9808 string.

• Serial

  • LiteX: Renamed the compatible from litex,uart0 to litex,uart.

• SPI

• USB

• Video

• Watchdog

• Wi-Fi

Networking

• ARP:

• CoAP:

• Connection manager:

• DHCPv4:

• DHCPv6:

• DNS/mDNS/LLMNR:

• gPTP/PTP:

• HTTP:

• IPSP:

• IPv4:

• IPv6:

• LwM2M: * Location object: optional resources altitude, radius, and speed can now be used optionally as per the location object’s specification. Users of these resources will now need to provide a read buffer.

  • lwm2m_senml_cbor: Regenerated generated code files using zcbor 0.9.0

• Misc:

• MQTT:

• Network Interface:

• OpenThread

• PPP

• Shell:

• Sockets:

• Syslog:

• TCP:

• Websocket:

• Wi-Fi:

• zperf:

USB

Devicetree

Kconfig

Libraries / Subsystems

• Debug

• Demand Paging

• Formatted output

• Management

  • MCUmgr

    • Added support for Enumeration Management Group, which allows for listing information on supported groups.

    • Fixed formatting of milliseconds in OS_MGMT_ID_DATETIME_STR by adding leading zeros.

• Logging

• Modem modules

• Power management

• Crypto

  • Mbed TLS was updated to version 3.6.1. The release notes can be found at: https://github.com/Mbed-TLS/mbedtls/releases/tag/mbedtls-3.6.1

  • The Kconfig symbol CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG_ALLOW_NON_CSPRNG was added to allow psa_get_random() to make use of non-cryptographically secure random sources when CONFIG_MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG is also enabled. This is only meant to be used for test purposes, not in production. (GitHub #76408)

  • The Kconfig symbol CONFIG_MBEDTLS_TLS_VERSION_1_3 was added to enable TLS 1.3 support from Mbed TLS. When this is enabled the following new Kconfig symbols can also be enabled:

    • CONFIG_MBEDTLS_TLS_SESSION_TICKETS to enable session tickets (RFC 5077);

    • CONFIG_MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_ENABLED for TLS 1.3 PSK key exchange mode;

    • CONFIG_MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_EPHEMERAL_ENABLED for TLS 1.3 ephemeral key exchange mode;

    • CONFIG_MBEDTLS_SSL_TLS1_3_KEY_EXCHANGE_MODE_PSK_EPHEMERAL_ENABLED for TLS 1.3 PSK ephemeral key exchange mode.

• CMSIS-NN

• FPGA

• Random

• SD

• Shell:

  • Reorganized the kernel threads and kernel stacks shell command under the L1 kernel thread shell command as kernel thread list & kernel thread stacks

  • Added multiple shell command to configure the CPU mask affinity / pinning a thread in runtime, do kernel thread -h for more info.

• State Machine Framework

• Storage

  • LittleFS: The module has been updated with changes committed upstream from version 2.8.1, the last module update, up to and including the released version 2.9.3.

• Task Watchdog

• POSIX API

• LoRa/LoRaWAN

• ZBus

HALs

• Nordic

• STM32

• ADI

• Espressif

MCUboot

OSDP

Trusted Firmware-M

LVGL

zcbor

• Updated the zcbor library to version 0.9.0. Full release notes at https://github.com/NordicSemiconductor/zcbor/blob/0.9.0/RELEASE_NOTES.md Migration guide at https://github.com/NordicSemiconductor/zcbor/blob/0.9.0/MIGRATION_GUIDE.md Highlights:

  • Many code generation bugfixes

  • You can now decide at run-time whether the decoder should enforce canonical encoding.

  • Allow –file-header to accept a path to a file with header contents

Tests and Samples

Issue Related Items

Known Issues