SDK upgrade guide
Zephyr 4.1 to Zephyr 4.2: what needs attention
Migratorisk's knowledge base lists 23 documented changes between Zephyr 4.1 and Zephyr 4.2. 23 of them are rated likely to break code, configuration or builds that use them. Below is each change, what a scan also reviews on this path, and how to see which ones apply to your project.
Find which of these affect your firmware
Migratorisk scans your project on your own computer and reports only the changes your code, configuration and build actually touch. Your source code is not uploaded.
python -m pip install migratorisk migratorisk scan --project ./your-firmware --from zephyr-4.1.0 --to zephyr-4.2.0 --out report.html
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Set up the local scanOr answer a few questions insteadWhere the changes are
What changes between Zephyr 4.1 and Zephyr 4.2
Ordered by impact. Each item names the release that introduced it and links to the official source. A change only matters if your project uses what changed; the scan checks that.
Devicetree compatibles renesas,ra-gpio and 4 more were removed
arduino_uno_r4_minima, arduino_uno_r4_wifi, and mikroe_clicker_ra4m1 have migrated to new FSP-based configurations. While there are no major functional changes, the device tree structure has been significantly revised. The following device tree bindings are now removed: renesas,ra-gpio, renesas,ra-uart-sci, renesas,ra-pinctrl, renesas,ra-clock-generation-circuit, and renesas,ra-interrupt-controller-unit. Covers 5 names.
Kconfig options CONFIG_REGULATOR_NPM1300 and 2 more were renamed
Renamed CONFIG_REGULATOR_NPM1300 to CONFIG_REGULATOR_NPM13XX, CONFIG_REGULATOR_NPM1300_COMMON_INIT_PRIORITY to REGULATOR_NPM13XX_COMMON_INIT_PRIORITY, CONFIG_REGULATOR_NPM1300_INIT_PRIORITY to CONFIG_REGULATOR_NPM13XX_INIT_PRIORITY. Covers 3 names.
APIs LINK_FULL_5000BASE_T and 1 more were renamed
Enums for the Ethernet speed have been renamed to be more independent of the used medium. Covers 2 names.
Kconfig options CONFIG_GPIO_NPM1300 and 1 more were renamed
Renamed CONFIG_GPIO_NPM1300 to CONFIG_GPIO_NPM13XX, CONFIG_GPIO_NPM1300_INIT_PRIORITY to CONFIG_GPIO_NPM13XX_INIT_PRIORITY. Covers 2 names.
Kconfig options CONFIG_MFD_NPM1300 and 1 more were renamed
Renamed CONFIG_MFD_NPM1300 to CONFIG_MFD_NPM13XX, CONFIG_MFD_NPM1300_INIT_PRIORITY to CONFIG_MFD_NPM13XX_INIT_PRIORITY. Covers 2 names.
Kconfig options CONFIG_WDT_NPM1300 and 1 more were renamed
Renamed CONFIG_WDT_NPM1300 to CONFIG_WDT_NPM13XX, CONFIG_WDT_NPM1300_INIT_PRIORITY to CONFIG_WDT_NPM13XX_INIT_PRIORITY. Covers 2 names.
API BT_AUDIO_CONTEXT_TYPE_PROHIBITED was renamed
BT_AUDIO_CONTEXT_TYPE_PROHIBITED has been renamed to BT_AUDIO_CONTEXT_TYPE_NONE.
API ETH_STM32_MODE_HALFDUPLEX was removed
The Kconfig options ETH_STM32_HAL_PHY_ADDRESS, ETH_STM32_CARRIER_CHECK, ETH_STM32_CARRIER_CHECK_RX_IDLE_TIMEOUT_MS, ETH_STM32_AUTO_NEGOTIATION_ENABLE, ETH_STM32_SPEED_10M, ETH_STM32_MODE_HALFDUPLEX have been removed, as they are no longer needed, and the driver now uses the ethernet phy api to communicate with the phy driver, which is responsible for configuring the phy settings.
API NET_REQUEST_ETHERNET_SET_AUTO_NEGOTIATION was removed
ETHERNET_CONFIG_TYPE_LINK, ETHERNET_CONFIG_TYPE_DUPLEX, ETHERNET_CONFIG_TYPE_AUTO_NEG and the related NET_REQUEST_ETHERNET_SET_LINK, NET_REQUEST_ETHERNET_SET_DUPLEX, NET_REQUEST_ETHERNET_SET_AUTO_NEGOTIATION have been removed. phy_configure_link together with net_eth_get_phy should be used instead to configure the link.
API PIXEL_FORMAT_RGB565 was replaced
On STM32 devices, the LTDC driver (st,stm32-ltdc) RGB565 format PIXEL_FORMAT_RGB565 has been replaced by PIXEL_FORMAT_BGR565 to match the format expected by Zephyr. This change ensures proper behavior of both display and video capture samples.
API TLS_CREDENTIAL_SERVER_CERTIFICATE was renamed
TLS credential type TLS_CREDENTIAL_SERVER_CERTIFICATE was renamed to more generic TLS_CREDENTIAL_PUBLIC_CERTIFICATE to better reflect the purpose of this credential type.
API bt_csip_set_member_get_sirk was removed
bt_csip_set_member_get_sirk has been removed. Use bt_csip_set_member_get_info to get the SIRK (and other information).
API counter_native_posix was renamed
counter_native_posix has been renamed counter_native_sim, and with it its kconfig options and DT binding. zephyr,native-posix-counter has been deprecated in favor of zephyr,native-sim-counter. And CONFIG_COUNTER_NATIVE_POSIX and its related options with CONFIG_COUNTER_NATIVE_SIM.
API ethernet_native_posix was renamed
ethernet_native_posix has been renamed ethernet_native_tap, and with it its kconfig options: CONFIG_ETH_NATIVE_POSIX and its related options have been deprecated in favor of CONFIG_ETH_NATIVE_TAP.
API fake_entropy_native_posix was renamed
fake_entropy_native_posix has been renamed fake_entropy_native_sim, and with it its kconfig options and DT binding. zephyr,native-posix-rng has been deprecated in favor of zephyr,native-sim-rng. And CONFIG_FAKE_ENTROPY_NATIVE_POSIX and its related options with CONFIG_FAKE_ENTROPY_NATIVE_SIM.
API native_posix_timer was renamed
native_posix_timer has been renamed native_sim_timer, and so its kconfig option CONFIG_NATIVE_POSIX_TIMER has been deprecated in favor of CONFIG_NATIVE_SIM_TIMER,.
API net_linkaddr_storage was renamed
The struct net_linkaddr_storage has been renamed to struct net_linkaddr and the old struct net_linkaddr has been removed. The struct net_linkaddr now contains space to store the link address instead of having pointer that point to the link address. This avoids possible dangling pointers when cloning struct net_pkt.
API uart_native_posix was renamed
uart_native_posix has been renamed uart_native_pty, and with it its kconfig options and DT binding. zephyr,native-posix-uart has been deprecated in favor of zephyr,native-pty-uart. CONFIG_UART_NATIVE_POSIX and its related options with CONFIG_UART_NATIVE_PTY.
Kconfig option CONFIG_BT_CSIP_SET_MEMBER_NOTIFIABLE was renamed
CONFIG_BT_CSIP_SET_MEMBER_NOTIFIABLE has been renamed to CONFIG_BT_CSIP_SET_MEMBER_SIRK_NOTIFIABLE.
Kconfig option CONFIG_BT_ISO_TX_FRAG_COUNT was removed
The CONFIG_BT_ISO_TX_FRAG_COUNT Kconfig option was removed as it was completely unused. Any uses of it can simply be removed.
Kconfig option CONFIG_LED_NPM1300 was renamed
Renamed CONFIG_LED_NPM1300 to CONFIG_LED_NPM13XX.
Kconfig option CONFIG_NPM1300_CHARGER was renamed
Renamed CONFIG_NPM1300_CHARGER to CONFIG_NPM13XX_CHARGER.
Kconfig option CONFIG_SPI_MCUX_LPSPI was renamed
Renamed CONFIG_SPI_MCUX_LPSPI to CONFIG_SPI_NXP_LPSPI, and similar for any child configs for that driver, including CONFIG_SPI_NXP_LPSPI_DMA and CONFIG_SPI_NXP_LPSPI_CPU.
What a scan of this path also reviews
Beyond the documented changes, Migratorisk reviews these upgrade risks for Zephyr projects on this path. Each one is reported only when the project shows the trigger.
Zephyr build logs need first-error triage after version changes
When it applies: Build logs often contain the highest-confidence migration breakage evidence.
Why it matters: First errors identify missing headers, renamed APIs, devicetree binding errors, and Kconfig failures.
What to do: Fix the first build error before chasing downstream compile or linker failures.
Zephyr devicetree and board files need target-version review
When it applies: Custom board and overlay files may depend on bindings or hardware model conventions from the source release.
Why it matters: Devicetree binding and board model changes commonly block Zephyr upgrades.
What to do: Validate custom board files, overlays, chosen nodes, and bindings against the target Zephyr release.
Zephyr Kconfig symbols need target-version review
When it applies: Project Kconfig files may contain symbols renamed, removed, or moved across Zephyr releases.
Why it matters: Zephyr version jumps often expose configuration drift before source changes compile.
What to do: Compare project Kconfig symbols against the target Zephyr release notes and build output.
Devicetree binding error in build log
When it applies: The build log reports a devicetree binding error.
Why it matters: Compatibles and bindings are renamed or split between releases; overlay and board errors must be fixed before source errors are meaningful.
What to do: Update overlays and board files to the target release bindings before addressing source errors.
Undefined Kconfig symbol in build log
When it applies: The build log reports an assignment to an undefined Kconfig symbol.
Why it matters: Zephyr renames and removes Kconfig options between releases, and Kconfig warnings abort the build before later errors appear.
What to do: Look up each undefined symbol in the migration guide of every release on the path and replace or remove it.
Zephyr source APIs need migration review
When it applies: Application source may use APIs whose signatures or headers changed between Zephyr releases.
Why it matters: Source API drift is common across major and multi-minor jumps.
What to do: Review source includes, driver APIs, Bluetooth APIs, kernel APIs, and subsystem-specific migration notes.
Zephyr west manifest revisions need target-version review
When it applies: Project manifests may pin modules that are incompatible with the target Zephyr release.
Why it matters: Module revisions, imports, and remotes can silently keep old APIs in the workspace.
What to do: Align manifest remotes, imports, and module revisions to the target Zephyr baseline.
Custom board needs the target Zephyr release devicetree and Kconfig review
When it applies: The project contains a custom board definition.
Why it matters: Board files track SoC devicetree, pinctrl, Kconfig and hardware model changes between releases.
What to do: Compare the custom board with a similar in-tree board in the target release (board.yml, chosen nodes, pinctrl, partitions, SoC Kconfig).
Verify OTA from the current field firmware
When it applies: The project uses MCUboot, so devices in the field keep their current bootloader after the upgrade.
Why it matters: The upgraded image must still be accepted by the existing bootloader (signature type, key, slot layout and image header).
What to do: Keep the signing key, signature type and slot layout unchanged, and test an OTA update from the current production image on hardware.
West manifest pins an older Zephyr revision
When it applies: west.yml pins a Zephyr or module revision.
Why it matters: The manifest must point at the target release, and pinned modules (HALs, MCUboot, Mbed TLS) must match it.
What to do: Update the zephyr revision in west.yml to the target tag, re-check pinned modules, then run west update.
Fix the first build error first
When it applies: The build log contains errors.
Why it matters: Later errors in an SDK upgrade are often caused by the first configuration or devicetree failure.
What to do: Resolve the first reported error, rebuild, and re-run the scan with the new build log.
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Related upgrade paths
Generated from the rule catalog of Migratorisk 0.3.0. This is an automated summary of published SDK changes, not a review of your project, and it does not replace builds and device tests. How the scanner is validated.