Migration guide to Zephyr v4.3.0 (Working Draft)

This document describes the changes required when migrating your application from Zephyr v4.2.0 to Zephyr v4.3.0.

Any other changes (not directly related to migrating applications) can be found in the release notes.

Build System 

device_init() Earlier releases returned a positive +errno value in case of device init failure due to a bug. This is now fixed to return the correct negative -errno value. Applications that implemented workarounds for this issue should now update their code accordingly.

UTF-8 utils declarations (utf8_trunc(), utf8_lcpy()) have been moved from util.h to a separate include/zephyr/sys/util_utf8.h file.

b_u585i_iot02a/ns: The flash layout was changed to be in sync with the upstream TF-M 2.2.1 board configurations. The new layout expands the flash partitions, moving the secondary ones to the external NOR flash. This change currently prevents upgrade from older Zephyr release images to Zephyr 4.3 release images. More details in the TF-M migration and release notes.
mimxrt11x0: renamed lpadc1 to lpadc2 and renamed lpadc0 to lpadc1.
NXP frdm_mcxa166 is renamed to frdm_mcxa346.
NXP frdm_mcxa276 is renamed to frdm_mcxa266.
Panasonic panb511evb is renamed to panb611evb.

Driver suppor for AXP2101 has been separated from the AXP192 one. As a consequence the kconfig symbol MFD_AXP192_AXP2101 is removed. MFD_AXP192 is now to be used for AXP192 device while MFD_AXP2101 for the AXP2101 one.

Nodes with compatible property st,stm32u5-otghs-phy now need to select the CLKSEL (phy reference clock) in the SYSCFG_OTGHSPHYCR register using the new property clock-reference. The selection directly depends on the value on OTGHSSEL (OTG_HS PHY kernel clock source selection) located in the RCC_CCIPR2 register.

Nodes with compatible property invensense,icm42688 now additionally need to also include invensense,icm4268x in order to work.

bt_le_cs_test_param and bt_le_cs_create_config_params now require providing both the main and sub mode as a single parameter.
bt_conn_le_cs_config now reports both the main and sub mode as a single parameter.
bt_conn_le_cs_main_mode and bt_conn_le_cs_sub_mode have been replaced with bt_conn_le_cs_mode.

bt_audio_codec_cfg now requires setting the target latency and target PHY explicitly, rather than always setting the target latency to “Balanced” and the target PHY to LE 2M. To keep current functionality, set the target_latency to BT_AUDIO_CODEC_CFG_TARGET_LATENCY_BALANCED and target_phy to BT_AUDIO_CODEC_CFG_TARGET_PHY_2M. The BT_AUDIO_CODEC_CFG macro defaults to these values. (GitHub #93825`)
Setting the BGS role for GMAP now requires also supporting and implementing the CONFIG_BT_BAP_BROADCAST_ASSISTANT. See the Basic Audio Profile (BAP) Broadcast Audio Assistant sample as a reference.
The BAP Scan Delegator will no longer automatically update the PA sync state, and bt_bap_scan_delegator_set_pa_state() must be used to update the state. If the BAP Scan Delegator is used together with the BAP Broadcast Sink, then the PA state of the receive state of a bt_bap_broadcast_sink will still be automatically updated when the PA state changes. (GitHub #95453`)

The deprecated ipm value was removed from bt-hci-bus devicetree property. ipc should be used instead.

The microchip,vsc8541 PHY driver now expects the reset-gpios entry to specify the GPIO_ACTIVE_LOW flag when the reset is being used as active low. Previously the active-low nature was hard-coded into the driver. (GitHub #91726).
CRC checksum generation offloading to hardware is now explicitly disabled rather then explicitly enabled in the Xilinx GEM Ethernet driver (xlnx,gem). By default, offloading is now enabled by default to improve performance, however, offloading is always disabled for QEMU targets due to the checksum generation in hardware not being emulated regardless of whether it is explicitly disabled via the devicetree or not. (GitHub #95435)
- Replaced devicetree property rx-checksum-offload which enabled RX checksum offloading disable-rx-checksum-offload which now actively disables it.
- Replaced devicetree property tx-checksum-offload which enabled TX checksum offloading disable-tx-checksum-offload which now actively disables it.

The HTTP server now respects the configured _config value. Check that you provide applicable value to HTTP_SERVICE_DEFINE_EMPTY, HTTPS_SERVICE_DEFINE_EMPTY, HTTP_SERVICE_DEFINE and HTTPS_SERVICE_DEFINE.

The RGB565 and BGR565 pixel formats were used interchangeably in the display sample. This has now been fixed. Boards and applications that were tested or developed based on the previous sample may be affected by this change (see GitHub #79996 for more information).
SSD1363’s properties using ‘greyscale’ now use ‘grayscale’.

The doc of ptp_clock_rate_adjust() API didn’t provide proper and clear function description. Drivers implemented it to adjust rate ratio relatively based on current frequency. Now PI servo is introduced in both PTP and gPTP, and this API function is changed to use for rate ratio adjusting based on nominal frequency. Drivers implementing ptp_clock_rate_adjust() should be adjusted to account for the new behavior.

The UART dictionary log parsing script scripts/logging/dictionary/log_parser_uart.py has been deprecated. Instead, the more generic script of scripts/logging/dictionary/live_log_parser.py should be used. The new script supports the same functionality (and more), but requires different command line arguments when invoked.

Callback operations now take an additional argument corresponding to the result code of the first error in the chain.
Callback operations are always called regardless of success/error status of previous submissions in the chain.

The size of psa_storage_uid_t, used to identify storage entries, was changed from 64 to 30 bits. This change breaks backward compatibility with previously stored entries for which authentication will start failing. Enable CONFIG_SECURE_STORAGE_64_BIT_UID if you are updating an existing installation from an earlier version of Zephyr and want to keep the pre-existing entries. (GitHub #94171)

The MQTT topics related to SHELL_BACKEND_MQTT have been renamed. Renamed <device_id>_rx to <device_id>/sh/rx and <device_id>_tx to <device_id>/sh/rx. The part after the <device_id> is now configurable via SHELL_MQTT_TOPIC_RX_ID and SHELL_MQTT_TOPIC_TX_ID. This allows keeping the previous topics for backward compatibility. (GitHub #92677).

The TinyCrypt library was removed as the upstream version is no longer maintained. PSA Crypto API is now the recommended cryptographic library for Zephyr.

Aligned the name of the Rail options with the other SiSDK related options:
- CONFIG_RAIL_PA_CURVE_HEADER to CONFIG_SILABS_SISDK_RAIL_PA_CURVE_HEADER
- CONFIG_RAIL_PA_CURVE_TYPES_HEADER to CONFIG_SILABS_SISDK_RAIL_PA_CURVE_TYPES_HEADER
- CONFIG_RAIL_PA_ENABLE_CALIBRATION to CONFIG_SILABS_SISDK_RAIL_PA_ENABLE_CALIBRATION
Fixed name of the CONFIG_SOC_*. These option contained PART_NUMBER in their while they shouldn’t.
The separate em3 power state was removed from Series 2 SoCs. The system automatically transitions to EM2 or EM3 depending on hardware peripheral requests for the oscillators.