Zephyr 4.2.0 (Working Draft)

We are pleased to announce the release of Zephyr version 4.2.0.

Major enhancements with this release include:

An overview of the changes required or recommended when migrating your application from Zephyr v4.1.0 to Zephyr v4.2.0 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:

More detailed information can be found in: https://docs.zephyrproject.org/latest/security/vulnerabilities.html

API Changes

Removed APIs and options

• Removed the deprecated the net_buf_put() and net_buf_get() API functions.

• Removed the deprecated include/zephyr/net/buf.h header file.

Deprecated APIs and options

• The scheduler Kconfig options CONFIG_SCHED_DUMB and CONFIG_WAITQ_DUMB were renamed and deprecated. Use CONFIG_SCHED_SIMPLE and CONFIG_WAITQ_SIMPLE instead.

• TLS credential type TLS_CREDENTIAL_SERVER_CERTIFICATE was renamed and deprecated, use TLS_CREDENTIAL_PUBLIC_CERTIFICATE instead.

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• arduino_uno_r4_minima and arduino_uno_r4_wifi board targets have been deprecated in favor of a new arduino_uno_r4 board with revisions (arduino_uno_r4@minima and arduino_uno_r4@wifi).

• esp32c6_devkitc board target has been deprecated and renamed to esp32c6_devkitc/esp32c6/hpcore.

New APIs and options

• I2C

  • i2c_configure_dt().

• Bluetooth

  • Audio

    • BT_BAP_ADV_PARAM_CONN_QUICK

    • BT_BAP_ADV_PARAM_CONN_REDUCED

    • BT_BAP_CONN_PARAM_SHORT_7_5

    • BT_BAP_CONN_PARAM_SHORT_10

    • BT_BAP_CONN_PARAM_RELAXED

    • BT_BAP_ADV_PARAM_BROADCAST_FAST

    • BT_BAP_ADV_PARAM_BROADCAST_SLOW

    • BT_BAP_PER_ADV_PARAM_BROADCAST_FAST

    • BT_BAP_PER_ADV_PARAM_BROADCAST_SLOW

    • bt_csip_set_member_set_size_and_rank()

    • bt_csip_set_member_get_info()

  • Host

    • bt_le_get_local_features()

    • bt_le_bond_exists()

    • bt_br_bond_exists()

    • bt_conn_lookup_addr_br()

    • bt_conn_get_dst_br()

    • LE Connection Subrating is no longer experimental.

• Display

  • display_clear()

• Networking:

  • IPv4

    • CONFIG_NET_IPV4_MTU

• Stepper

  • stepper_stop()

New Boards

New Drivers

New Samples

• Stepper

Other notable changes

• Added support for Armv8.1-M MPU’s PXN (Privileged Execute Never) attribute. With this, the MPU attributes for __ramfunc and __ram_text_reloc were modified such that, PXN attribute is set for these regions if compiled with CONFIG_ARM_MPU_PXN and CONFIG_USERSPACE. This results in a change in behaviour for code being executed from these regions because, if these regions have pxn attribute set in them, they cannot be executed in privileged mode.