Hello Zephyr developers! The first release candidate for Zephyr 4.4.0 has been tagged: https://github.com/zephyrproject-rtos/zephyr/releases/tag/v4.4.0-rc1 The merge window for features and enhancements is now closed for this release, and it will remain closed until 4.4.0 is released. We are now in the stabilization phase, and only bug-fix, documentation and stabilization patches may be merged to the main branch. Additional features and enhancements, including new hardware support for the 4.4.0 release requires approval by the TSC. While matching bug reports for pull requests are welcome and encouraged, we will not enforce this until rc2, if the pull request is clearly a bug fix. You may continue to submit pull requests for new features to gather feedback early or collaborate with others, but the release team would like to encourage everyone to focus on testing, documentation improvements and fixing bugs. We anticipate the coming weeks to be very busy reducing overall bug count. Please give this RC a test drive and report any issues on supported platforms (with a PR if possible). Release milestone dates: https://github.com/zephyrproject-rtos/zephyr/wiki/Release-Management Release process: https://docs.zephyrproject.org/latest/project/release_process.html Regards, The release team.

This is a bugfix release for Zephyr 4.2.0. The following issues are addressed by this release: - #96197 gPTP sample does not boot with NUCLEO-H563ZI - #92393 LIS2DUX12 setting incorrect ODR configuration - #93011 stm32u0: interrupt vectors for lpuart1 and lpuart2 are wrong in device tree - #93220 Twister tests with coverage enabled crash during startup - #93265 Stm32u5x: clock disable in sleep mode fix causing USB HS device initialization stalls - #93342 doc: Documentation issue in 'connectivity/networking/api/tftp' - #93350 net: tcp: keep-alive "pings" are no longer acknowledged with v4.2.0 - #93364 tests/subsys/llext fails after tagging 4.2 - #93424 Missing break after IPV6_MULTICAST_IF option processing - #93445 STM32U535/545: dtc error for node wkup-pin@8 referencing non-existent port gpiof - #93519 drivers: nxp_lpspi: Large performance degradation - #93594 Nicla Vision has bad I2C address for VL53L1X sensor - #93611 doc: Documentation issue in 'releases/release-notes-4.2' - #93790 drivers: console: posix_arch_console: build warning with ``CONFIG_PRINTK=n`` - #93792 USB samples not working on ``max32690evkit`` - #93831 drivers: can: nrf: fix invalid pointer leading to undef behavior - #93839 I3C: STM32: Has a Mutex deadlock on DAA Failure - #94000 EXT2 fs_stat on mount point fails with a NULL pointer dereference. - #94047 Shell device name tab completion for regulator parents show incorrect names - #94063 SPI loopback tests failing on MAX32 SoCs. - #94083 stm32: u3: low clock frequency for the RNG periphera - #94093 Build error when OCRAM node is disabled in device tree (status = "disabled") [NXP RT1061] - #94107 ppp link-layer address configuration is wrong - #94325 iar: incorrect assembler optimzation flag - #94473 LVGL Widgets Demo stopped working in v4.1 on mimxrt1060_evk@A - #94702 Locally Administered Address (LAA) bit missing for STM32 ethernet driver - #94703 Locally Administered Address (LAA) bit set on wrong index for NXP i.MX ethernet driver - #94774 modules/picolibc: Roll back unnecessary changes, synchronize with SDK 0.17.4 - #94812 ``nocache`` data is included in ROM section - #94842 iar: Zephyr 4.2 fails with IAR EWARM 9.70.1 - #94954 Spurious error log "No valid legacy adv to resume" in bt_hci_le_enh_conn_complete when using bt_le_ext_adv_start() - #95113 gpio_pin_get_config for STM32 returns wrong flags value for input pins - #95146 i2c: stm32: non-RTIO driver fixes on PM and on STM32F7 from Zephyr v4.3 - #95297 Links to the pyOCD repository are outdated - #95456 Zephyr Netstack buffer leaks - #95580 Picolibc module and SDK are not in sync for Zephyr 4.2.0 - #95721 Boards documentation: "arm" Architecture not specified at least for STM32MP13 and STM32N6 boards - #95724 drivers: i2c: stm32: build error when using DMAs with st,stm32-i2c-v2 driver - #95768 Possible TCP connection leak when creating a socket - #95850 Applications do not watch MCUboot key file for changes - #96087 TCP connection sends an incorrect seqnum FIN message - #96172 arch: arm: switch to privilege stack in SVC handler - #96768 incorrect i2c3 base address on stm32f303Xe

The third release candidate for Zephyr 4.2.0 has been tagged: https://github.com/zephyrproject-rtos/zephyr/releases/tag/v4.2.0-rc3 The merge window for features and enhancements remains closed until 4.2.0 is released. We continue in the stabilization phase, and only blocker bug-fixes and documentation patches may be merged to the main branch. As a reminder to maintainers- please send PRs to update the release notes and migration guide for any areas you manage. You may continue to submit pull requests for new features to gather feedback early or collaborate with others, but the release team would like to encourage everyone to focus on testing, fixing any blocker bugs found, and finalizing release notes. Other bugs which are not critical enough to be categorized as blocker, but should still be part of 4.2 should be marked with the `backport v4.2-branch` label so they can be considered for the first dot release. Dan and Dan, and the full Zephyr Release Team Release milestone dates: https://github.com/zephyrproject-rtos/zephyr/wiki/Release-Management Release process: https://docs.zephyrproject.org/latest/project/release_process.html Blocker bugs process: https://docs.zephyrproject.org/latest/project/release_process.html#blocker-bugs

The second release candidate for Zephyr 4.2.0 has been tagged: https://github.com/zephyrproject-rtos/zephyr/releases/tag/v4.2.0-rc2 The merge window for features and enhancements remains closed until 4.2.0 is released. We continue in the stabilisation phase, and only bug-fix, documentation and stabilisation patches may be merged to the main branch. You may continue to submit pull requests for new features to gather feedback early or collaborate with others, but the release team would like to encourage everyone to focus on testing, fixing and helping triage bugs. Release milestone dates: https://github.com/zephyrproject-rtos/zephyr/wiki/Release-Management Release process: https://docs.zephyrproject.org/latest/project/release_process.html Dan and Dan, and the full Zephyr Release Team

The first release candidate for Zephyr 4.2.0 has been tagged: https://github.com/zephyrproject-rtos/zephyr/releases/tag/v4.2.0-rc1 The merge window for features and enhancements is now closed for this release, and it will remain closed until 4.2.0 is released. We are now in the stabilisation phase, and only bug-fix, documentation, and stabilisation patches may be merged to the main branch. Additional features and enhancements, including new hardware support for the 4.2.0 release requires approval by the TSC. You may continue to submit pull requests for new features to gather feedback early or collaborate with others, but the release team would like to encourage everyone to focus on testing, documentation improvements and fixing bugs. We anticipate the coming weeks to be very busy reducing overall bug count. Please give this RC a test drive and report any issues on supported platforms (with a PR if possible). Release milestone dates: https://github.com/zephyrproject-rtos/zephyr/wiki/Release-Management Release process: https://docs.zephyrproject.org/latest/project/release_process.html Dan and Dan, and the full Zephyr Release Team

We are pleased to announce the release of [Zephyr 4.1.0](https://github.com/zephyrproject-rtos/zephyr/releases/tag/v4.1.0)! For a detailed overview of some of the highlights of this release, you may check out the [dedicated article that was posted](https://zephyrproject.org/zephyr-rtos-4-1-is-available) on the Zephyr blog, and its [accompanying video](https://youtu.be/TOIwI9XrHZM). Major enhancements with this release include: ## Performance improvements Multiple performance improvements of core Zephyr kernel functions have been implemented, benefiting all supported hardware architectures. An official port of the thread_metric RTOS benchmark has also been added to make it easier for developers to measure the performance of Zephyr on their hardware and compare it to other RTOSes. ## Experimental support for IAR compiler IAR Arm Toolchain can now be used to build Zephyr applications. This is an experimental feature that is expected to be improved in future releases. Initial support for Rust on Zephyr It is now possible to write Zephyr applications in Rust. Rust Language Support is available through an optional Zephyr module, and several code samples are available as a starting point. ## USB MIDI Class Driver Introduction of a new USB MIDI 2.0 device driver, allowing Zephyr devices to communicate with MIDI controllers and instruments over USB. ## Expanded Board Support Support for 70 new boards and 11 new shields has been added in this release. This includes highly popular boards such as Raspberry Pi Pico 2 and WCH CH32V003EVT, several boards with CAN+USB capabilities making them good candidates for running the Zephyr-based open source CANnectivity firmware, and dozens of other boards across all supported architectures. The full release notes and list of major changes since the last release can be found here: https://docs.zephyrproject.org/latest/releases/release-notes-4.1.html An overview of the changes required or recommended when migrating your application from Zephyr v4.0.0 to Zephyr v4.1.0 can be found in the migration guide:https://docs.zephyrproject.org/latest/releases/migration-guide-4.1.html This 4.1 release will be supported until November 14th, 2025. Many thanks to the 678(!) individuals who contributed to this release! 🚀 Benjamin and Fabio.

This is an LTS maintenance release with fixes. Issues fixed ************ These GitHub issues were addressed since the previous 3.7.0 tagged release: * :github:`77088` - net: buf: Pre-initialize user_data on net_buf_alloc() * :github:`81380` - test: twister: hwmap: missing serial_pty definition * :github:`81570` - ESP32 fails on assert when WiFi enabled * :github:`81083` - DA1469x dma driver initialization fails * :github:`80542` - Hard fault on boot w/ GCC 14 on Cortex-M * :github:`71896` - xtensa: remove unnecessary padding in arch_mem_domain * :github:`81372` - arch: riscv: userspace: potential security risk when CONFIG_RISCV_GP=y * :github:`42227` - Teensy41 support SDHC - Storage init Error * :github:`66800` - [Coverity CID: 338107] Division or modulo by zero in subsys/shell/backends/shell_uart.c * :github:`70498` - cellular_modem: Pinnacle 100 does not work with CONFIG_UART_INTERRUPT_DRIVEN * :github:`71397` - Espressif HAL5.1 - Core panic'ed on EPS32S3 with hello_world sample * :github:`71916` - Bump minimum Python version (3.10?) ahead of LTSv3 release * :github:`74291` - Multiple USB contexts for same device lead to bus faults * :github:`74750` - [Coverity CID: 353644] Unintended sign extension in drivers/sensor/ams/tsl2591/tsl2591.c * :github:`74752` - [Coverity CID: 353654] Unintended sign extension in drivers/sensor/ams/tsl2591/tsl2591.c * :github:`75256` - [Coverity CID: 394233] Division or modulo by zero in drivers/sensor/tdk/icm42688/icm42688.h * :github:`75257` - [Coverity CID: 394232] Division or modulo by zero in drivers/sensor/tdk/icm42688/icm42688.h * :github:`75265` - display: stm32-ltdc: incorrect return value for blanking on/off calls when panel controller is not passed in DT * :github:`75318` - Zephyr 3.7 RC2 BLE on STM32 Nucleo WB55 does not work * :github:`75319` - `fatal error: sys/_timespec.h: No such file or directory` with v3.7.0-rc2 * :github:`75427` - `CONFIG_MBEDTLS_PEM_CERTIFICATE_FORMAT` is misleading as it only enables PEM parsing * :github:`75676` - tests: dma: chan_blen_transfer: test breakage on Nucleo-H743ZI * :github:`75686` - ST LIS2DUX12 driver: temperature is not converted to Celsius and raw values are returned * :github:`75736` - Logging stops on all backend when overloaded for a time * :github:`75758` - ST LIS2DUX12 driver: will not correctly read values on big-endian HW * :github:`75834` - xtensa: mpu: adding or removing partitions from memory domain of current running thread has no effect * :github:`75853` - C++: Boot fails with global STL objects * :github:`75909` - CONFIG_NET_NATIVE_OFFLOADED_SOCKETS fails after DTLS handshake * :github:`75912` - RAM retention not working on NXP S32K3 * :github:`75967` - bl5340_dvk LCD does not work * :github:`76000` - coap: block_number in coap_get_block1_option() is too small * :github:`76090` - TF-M: builds download source from external git repository * :github:`76185` - scripts: 'west blobs fetch' does not verify digests after downloading * :github:`76254` - linker: section_tags: missing include * :github:`76268` - Bluetooth: PAwR Sync does not compile without PAST receiver compiled in * :github:`76325` - ESP32S3: Zephyr freezes during OTA Update over UDP and BLE * :github:`76360` - Crash if enabling v4-mapping-to-v6 and DHCPv4 * :github:`76397` - gdbstub: compilation error on ARM * :github:`76398` - arch: riscv: stacktrace: user thread stack bound check is wrong * :github:`76403` - net: wifi: NM type check is incorrect * :github:`76427` - CONFIG_BT_CTLR_OPTIMIZE_FOR_SPEED not selected by default in zephyr 3.7 * :github:`76446` - drivers: mdio: mdio_nxp_enet: Link goes up and down sporadically * :github:`76447` - Odroid Go Boot Failure * :github:`76471` - TCP Delay ACK in case no PSH flag is present causing extremly low download throughput for some clients * :github:`76519` - Get I3C basic device fails for devices that do not support GETCAP * :github:`76549` - Bug in STM32 Disco L475 Arduino I2C header * :github:`76551` - Bluetooth: USB Audio Starvation in BAP Broadcast Sink Sample * :github:`76603` - sensortile_box_pro board does not support hts221 sensor * :github:`76607` - Fixes an uninitialized value in lis2dux12 * :github:`76625` - drivers: usb: stm32 udc driver get the global otg interrupt * :github:`76655` - RT11xx device tree build warnings * :github:`76717` - Check L2 send properly for offloaded ifaces * :github:`76718` - PTP - incorrect clock offset calculation * :github:`76737` - Bluetooth L2CAP TX fragmentation state not cleared upon disconnect * :github:`76738` - Sending Bluetooth L2CAP messages after reconnecting sometimes leads to crashes due to uninitalized net_buf callback * :github:`76747` - CONFIG_DEVICE_DT_METADATA=y not tested with usespace enabled * :github:`76762` - arch: riscv: stacktrace: trace is incomplete when unwinding from function without callee * :github:`76776` - http1 dynamic post request response doesn't send header a second time * :github:`76912` - drivers/bluetooth/hci/userchan.c build waring w gcc13 * :github:`76932` - Compilation error on Ubuntu 24.04 when CONFIG_FUSE_FS_ACCESS=y * :github:`77006` - Bluetooth: Host: ISO buffer not unreffed * :github:`77007` - Bluetooth: Host: ISO not clearing TX context on disconnect * :github:`77078` - manifest: update percepio * :github:`77089` - nxp: lpc55sxx: sram node address error * :github:`77096` - nxp lpc55xx will crash when trying to use a nxp,ctimer-pwm DTS node * :github:`77126` - RTC RV3028 clock output disabled by enabling alarm/update callback * :github:`77129` - NXP's IMX RT1010 triggers assert on SPI Loopback test when EDMA enabled * :github:`77175` - SCSI Read Capacity reports wrong capacity when used with USB Mass storage device * :github:`77188` - Unaligned 32-bit reads following casts on dns_socket_dispatcher::local_addr (Cortex-M0) * :github:`77221` - Websocket compile issue if Posix API is not set * :github:`77241` - bluetooth: Behavior change in host causing MESH to fail on sending messages * :github:`77269` - da1469x: entropy and gpio drivers throw assertions * :github:`77303` - net: socket: recvmsg() doesn't update msg_controllen accordingly * :github:`77371` - RT11xx bus clocks set incorrectly * :github:`77396` - doc: Documentation scrolling does not work with arrow keys * :github:`77424` - IMXRT11xx secondary core improperly deinit the ENET PLL * :github:`77545` - modules: percepio: Fix python executable name in CMakeLists.txt * :github:`77557` - drivers: ethernet: nxp_enet: Fused MAC address handling is wrong * :github:`77594` - Bluetooth: Failures in unit tests * :github:`77633` - drivers: dai: nxp: sai: RTOS crashes on TX/RX underrun/overrun * :github:`77658` - backported PRs maintain fail status after issues are added to the PR description * :github:`77669` - BLE EDTT GATT tests fail with python >= 3.11 * :github:`77784` - STM32 I2S Driver Clock Configuration * :github:`77824` - llext samples fail with BUS ERROR (zephyr-3.7 stable) * :github:`77952` - ESP32: Interrupts with ISRs in flash are not disabled during flash operations * :github:`78138` - riscv: plic: IRQs may not be enabled in non-zero HART * :github:`78146` - mDNS reponder might fail to serve if mDNS resolver is enabled * :github:`78244` - arch: riscv: IRQ stacks of secondary cores are not initialized to `0xAA` when `CONFIG_INIT_STACKS=y` * :github:`78263` - building samples/cpp/hello_world reports "undefined reference to `_impure_ptr` error * :github:`78268` - LPC55xx USB not working with SPEED_OPTIMIZATIONS=y * :github:`78490` - net: l2: ieee802154: IEEE-802.15.4 packets dropped when CONFIG_NET_L2_IEEE802154_SECURITY is enabled * :github:`78494` - subsys: net: socket_tls: Connection vanishes -> Caller blocked forever * :github:`78495` - net: l2: ieee802154: ctx_lock taken but not given * :github:`78608` - Bluetooth: classic: avdtp: missing buffer length check * :github:`78622` - Wrong package for bz2 * :github:`78651` - drivers: PHY Microchip KSZ8081 will block system work queue for 500/1000ms * :github:`78724` - net: checksum offloading not working for virtual network interfaces used for Virtual LAN (VLAN) * :github:`78769` - backport: v3.7: dts: arm: st: stm32h5: fix spi 1-3 clocks * :github:`78927` - doc: mcumgr: Wrong license for mcumgr-client * :github:`79208` - sysbuild: ExternalZephyrProject_Add() cannot cope with hwmv2 board and revision * :github:`79288` - driver: clock-control: imx-ccm-rev2: get_rate(FLEXSPI2) returns FLEXSPI1 clock rate * :github:`79298` - arch: riscv: the `s0` dumped during a fatal error is not correct * :github:`79301` - arch: irq: multilevel: the value return from `irq_parent_level_3()` is wrong * :github:`79518` - Temporary Modbus Client "Soft Lock" * :github:`79576` - Dependencies for `SOC_FLASH_MCUX` are incorrect on LPC55xxx platforms * :github:`79788` - net: ip: igmp: IGMPv2 does not work when IGMPv3 is enabled * :github:`79800` - stream_flash: stream_flash_erase_page does not check whether requested offset is in range of stream flash owned area * :github:`79947` - ESP32 touch_sensor not working * :github:`80005` - doc: Documentation issue in 'contribute/documentation/guidelines' * :github:`80134` - up_squared: tests/arch/x86/info/arch.x86.info.userspace [timeout] * :github:`80200` - CMake: Find package with version ranges are ignored for Zephyr SDK * :github:`80383` - drivers: flash: spi_nor: values vom DT not correctly used, when `CONFIG_SPI_NOR_SFDP_RUNTIME=y` * :github:`80429` - Bug in ACD implementation RFC5227 * :github:`80476` - mgmt: mcumgr: stat_mgmt: stat_mgmt_list always send legacy behavior * :github:`80541` - Incorrect part number LPC55S69 in Konfig.soc * :github:`80593` - Not possible to write beyond 16MB using flash sample on FRDM_RW612 * :github:`80701` - Changes to cortex_m swap code have major impact on kernel context switching times. * :github:`80723` - testsuite: coverage: application unable to include `coverage.h` * :github:`80750` - drivers: can: sam: wrong MRBA configuration * :github:`80810` - samples: subsys: mgmt: mcumgr: smp_svr: UDP overlay missing random selection * :github:`80818` - shell: shell_help: terminal offset of subcommands' help text isn't aligned Mbed TLS ******** Mbed TLS was updated to version 3.6.2 (from 3.6.0). The release notes can be found at: * https://github.com/Mbed-TLS/mbedtls/releases/tag/mbedtls-3.6.1 * https://github.com/Mbed-TLS/mbedtls/releases/tag/mbedtls-3.6.2 Mbed TLS 3.6 is an LTS release that will be supported with security and bug fixes until at least March 2027. MCUboot ******* MCUboot commit has been updated to ``ea2410697dd0262edec041a0ccb07fdbde7c1aff``. Trusted Firmware-M ****************** TF-M was updated to version 2.1.1 (from 2.1.0). The release notes can be found at: * https://trustedfirmware-m.readthedocs.io/en/tf-mv2.1.1/releases/2.1.1.html TF-M 2.1 is an LTS release synchronized with Mbed TLS 3.6 that will be supported with security and bug fixes until March 2027.

TODO: add release overview and notes link