doc/releases/migration-guide-4.0.rst

:orphan:

.. _migration_4.0:

Migration guide to Zephyr v4.0.0 (Working Draft)
################################################

This document describes the changes required when migrating your application from Zephyr v3.7.0 to
Zephyr v4.0.0.

Any other changes (not directly related to migrating applications) can be found in
the :ref:`release notes<zephyr_4.0>`.

.. contents::
    :local:
    :depth: 2

Build System
************

Kernel
******

Boards
******

* :ref:`native_posix<native_posix>` has been deprecated in favour of
  :ref:`native_sim<native_sim>` (:github:`76898`).

Modules
*******

Mbed TLS
========

* The Kconfig options ``CONFIG_MBEDTLS_TLS_VERSION_1_0`` and ``CONFIG_MBEDTLS_TLS_VERSION_1_1``
  have been removed because Mbed TLS doesn't support TLS 1.0 and 1.1 anymore since v3.0. (:github:`76833`)

Trusted Firmware-M
==================

LVGL
====

Device Drivers and Devicetree
*****************************

* The ``compatible`` of the LiteX ethernet controller has been renamed from
  ``litex,eth0`` to :dtcompatible:`litex,liteeth`. (:github:`75433`)

* The ``compatible`` of the LiteX uart controller has been renamed from
  ``litex,uart0`` to :dtcompatible:`litex,uart`. (:github:`74522`)

* The devicetree bindings for the Microchip ``mcp23xxx`` series have been split up. Users of
  ``microchip,mcp230xx`` and ``microchip,mcp23sxx`` should change their devicetree ``compatible``
  values to the specific chip variant, e.g. :dtcompatible:`microchip,mcp23017`.
  The ``ngpios`` devicetree property has been removed, since it is implied by the model name.
  Chip variants with open-drain outputs (``mcp23x09``, ``mcp23x18``) now correctly reflect this in
  their driver API, users of these devices should ensure they pass appropriate values to
  :c:func:`gpio_pin_set`. (:github:`65797`)

Controller Area Network (CAN)
=============================

Display
=======

Enhanced Serial Peripheral Interface (eSPI)
===========================================

GNSS
====

Input
=====

* :c:macro:`INPUT_CALLBACK_DEFINE` has now an extra ``user_data`` void pointer
  argument that can be used to reference any user data structure. To restore
  the current behavior it can be set to ``NULL``. A ``void *user_data``
  argument has to be added to the callback function arguments.

* The :dtcompatible:`analog-axis` ``invert`` property has been renamed to
  ``invert-input`` (there's now an ``invert-output`` available as well).

Interrupt Controller
====================

LED Strip
=========

Sensors
=======

Serial
======

Regulator
=========

* Internal regulators present in nRF52/53 series can now be configured using
  devicetree. The Kconfig options :kconfig:option:`CONFIG_SOC_DCDC_NRF52X`,
  :kconfig:option:`CONFIG_SOC_DCDC_NRF52X_HV`,
  :kconfig:option:`CONFIG_SOC_DCDC_NRF53X_APP`,
  :kconfig:option:`CONFIG_SOC_DCDC_NRF53X_NET` and
  :kconfig:option:`CONFIG_SOC_DCDC_NRF53X_HV` selected by board-level Kconfig
  options have been deprecated.

  Example for nRF52 series:

  .. code-block:: devicetree

      /* configure REG/REG1 in DC/DC mode */
      &reg/reg1 {
          regulator-initial-mode = <NRF5X_REG_MODE_DCDC>;
      };

      /* enable REG0 (HV mode) */
      &reg0 {
          status = "okay";
      };

  Example for nRF53 series:

  .. code-block:: devicetree

      /* configure VREGMAIN in DC/DC mode */
      &vregmain {
          regulator-initial-mode = <NRF5X_REG_MODE_DCDC>;
      };

      /* configure VREGRADIO in DC/DC mode */
      &vregradio {
          regulator-initial-mode = <NRF5X_REG_MODE_DCDC>;
      };

      /* enable VREGH (HV mode) */
      &vregh {
          status = "okay";
      };

Bluetooth
*********

Bluetooth HCI
=============

Bluetooth Mesh
==============

Bluetooth Audio
===============

* The Volume Renderer callback functions :code:`bt_vcp_vol_rend_cb.state` and
  :code:`bt_vcp_vol_rend_cb.flags` for VCP now contain an additional parameter for
  the connection.
  This needs to be added to all instances of VCP Volume Renderer callback functions defined.
  (:github:`76992`)

Bluetooth Classic
=================

Bluetooth Host
==============

Bluetooth Crypto
================

Networking
**********

* The CoAP public API functions :c:func:`coap_get_block1_option` and
  :c:func:`coap_get_block2_option` have changed. The ``block_number`` pointer
  type has changed from ``uint8_t *`` to ``uint32_t *``. Additionally,
  :c:func:`coap_get_block2_option` now accepts an additional ``bool *has_more``
  parameter, to store the value of the more flag. (:github:`76052`)

* The Ethernet bridge shell is moved under network shell. This is done so that
  all the network shell activities can be found under ``net`` shell command.
  After this change the bridge shell is used by ``net bridge`` command.

Other Subsystems
****************

Flash map
=========

hawkBit
=======

MCUmgr
======

Modem
=====

Architectures
*************