Zephyr 4.4.0 (Working Draft)

We are pleased to announce the release of Zephyr version 4.4.0.

Major enhancements with this release include:

An overview of the changes required or recommended when migrating your application from Zephyr v4.3.0 to Zephyr v4.4.0 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:

• CVE 2025-53022 (TF-M) FWU does not check the length of the TLV’s payload

API Changes

Removed APIs and options

Deprecated APIs and options

• Bluetooth

  • Mesh

    • The function bt_mesh_input_number() was deprecated. Applications should use bt_mesh_input_numeric() instead.

    • The callback output_number in bt_mesh_prov structure was deprecated. Applications should use output_numeric callback instead.

  • Host

    • bt_conn_le_info.interval has been deprecated. Use bt_conn_le_info.interval_us instead. Note that the units have changed: interval was in units of 1.25 milliseconds, while interval_us is in microseconds.

New APIs and options

• Audio

  • PDM_DT_IO_CFG_GET

  • PDM_DT_HAS_LEFT_CHANNEL

  • PDM_DT_HAS_RIGHT_CHANNEL

• Bluetooth

  • Host

    • bt_gatt_cb_unregister() Added an API to unregister GATT callback handlers.

  • Mesh

    • bt_mesh_input_numeric() to provide provisioning numeric input OOB value.

    • output_numeric callback in bt_mesh_prov structure to output numeric values during provisioning.

  • Services

    • Introduced Alert Notification Service (ANS) CONFIG_BT_ANS

• Ethernet

  • Driver MAC address configuration with support for NVMEM cell.

    • net_eth_mac_load()

    • net_eth_mac_config

    • NET_ETH_MAC_DT_CONFIG_INIT and NET_ETH_MAC_DT_INST_CONFIG_INIT

• Flash

  • jedec,mspi-nor now allows MSPI configuration of read, write and control commands separately via devicetree.

• Modem

  • CONFIG_MODEM_HL78XX_AT_SHELL

  • CONFIG_MODEM_HL78XX_AIRVANTAGE

• NVMEM

  • Flash device support

    • CONFIG_NVMEM_FLASH

    • CONFIG_NVMEM_FLASH_WRITE

• PWM

  • Extended API with PWM events

    • pwm_event_callback to hold a pwm event callback

    • pwm_init_event_callback() to help initialize a pwm_event_callback object

    • pwm_add_event_callback() to add a callback

    • pwm_remove_event_callback() to remove a callback

    • manage_event_callback in pwm_driver_api to manage pwm events

    • CONFIG_PWM_EVENT

• Power

  • The new voltage-scale property of st,stm32u5-pwr can be used to select the voltage scale manually on STM32U5 series via Devicetree. This notably enables usage of the USB controller at lower system clock frequencies.

• Settings

  • CONFIG_SETTINGS_SAVE_SINGLE_SUBTREE_WITHOUT_MODIFICATION

  • CONFIG_SETTINGS_SAVE_SINGLE_SUBTREE_WITHOUT_MODIFICATION_VALUE_SIZE

New Boards

• Ai-Thinker Co., Ltd.

  • Ai-Thinker M61-32S development board (ai_m61_32s_kit)

  • Rename ai_m62_12f and ai_wb2_12f to ai_m62_12f_kit and ai_wb2_12f_kit

New Shields

New Drivers

• Radio

  • radio-fem-two-ctrl-pins (renamed from generic-fem-two-ctrl-pins)

  • radio-gpio-coex (renamed from gpio-radio-coex)

New Samples

• Peripheral ANS

Libraries / Subsystems

Other notable changes

• TF-M was updated to version 2.2.2 (from 2.2.0). The release notes can be found at:

  • https://trustedfirmware-m.readthedocs.io/en/tf-mv2.2.2/releases/2.2.1.html

  • https://trustedfirmware-m.readthedocs.io/en/tf-mv2.2.2/releases/2.2.2.html