Zigbee - 802.15.4 Mesh + BLE Multiprotocol Version 9.1.1 (Jul 29, 2026) - Release Notes#

Zigbee Version 9.1.1

This document provides release information for the 802.15.4 Mesh + BLE Multiprotocol SDK.

Click here for earlier releases.

Release Summary#

Key Features | API Changes | Bug Fixes | Chip Enablement

Key Features#

Added in 9.1.0#

  • Concurrent Multiprotocol (CMP) co-processor sample applications running Zigbee NCP, OpenThread RCP, and Bluetooth RCP

  • ZigbeeD + OTBR support on Android 15 – Alpha

  • Standardized Multiprotocol sample application names, project layout, and Simplicity Studio display titles

  • Reorganization of multiprotocol packages: file paths of components and applications have been re-organized to give multiprotocol packages a more cohesive file structure

API Changes#

sl_802154_radio_set_scheduler_priorities() has been removed.

Bug Fixes#

Fixed in 9.1.0#

Targeted quality improvements and bug fixes across Zigbee + OpenThread + BLE Dynamic Multiprotocol and Concurrent Multiprotocol applications on Series 2 and Series 3 devices.

Fixed in Revision 1#

Targeted quality improvements and bug fixes.

Chip Enablement#

Added in 9.1.0#

None.

Key Features#

New Features | Enhancements | Removed Features | Deprecated Features

New Features#

Added in 9.1.0#

CMP + BLE-RCP sample applications (Zigbee NCP + OpenThread RCP + Bluetooth RCP)#

Added new Concurrent Multiprotocol (CMP) co-processor sample projects that run Zigbee NCP, OpenThread RCP, and Bluetooth RCP on one EFR device. The Bluetooth side exposes a BLE controller over CPC so a Linux host can use the Silicon Labs RCP with CPCd and a standard Bluetooth stack (i.e. BlueZ). Zigbee and OpenThread host applications use the same CPC multiplexer model as existing NCP / RCP designs.

Variants:

Project

Host link

mp-zb-ncp-ot-rcp-ble-rcp-uart

UART (VCOM-style link; configurable baud / flow control)

mp-zb-ncp-ot-rcp-ble-rcp-spi

SPI

Details:

  • CPC multiplexes Zigbee NCP, OpenThread RCP, and BLE HCI over a single physical interface (UART or SPI) to the host.

  • BLE is included as Bluetooth controller + HCI over CPC (bluetooth_hci_cpc), suitable for pairing with host-side CPC and Bluetooth middleware.

  • Zigbee NCP behavior aligns with existing zigbee_ncp_cpc-based samples; optional NCP extensions remain supported as described in the project description.

  • OpenThread is provided as RCP with ot_ncp_cpc for Spinel / CPC toward the host.

  • Bluetooth Controller component configuration was added and updated for RCP applications, including the new SL_BTCTRL_RTOS_LINK_LAYER_TASK_STACK_SIZE parameter in the .slcp files (minimum value 1100 on Series 2, default 1400 on Series 3) to allow fine-tuning the BLE link-layer task stack size based on application requirements.

ZigbeeD + OTBR on Android 15 — Alpha#

Added Alpha support for Android 15 host development with Multiprotocol. The release includes ZigbeeD libraries and the source code needed to build the ZigbeeD and OpenThread Border Router (OTBR) host applications. The Android-15 host build uses NDK r27d and ships through dedicated container and packaging scripts.

Enhancements#

Changed in 9.1.0#

Standardized Multiprotocol sample application names#

Standardized Multiprotocol sample application names across Simplicity Studio labels, SLCP project_name values, filenames, and directory layout under multiprotocol_app/. The coordinated scheme groups examples by protocol combination and architecture, uses a common mp- prefix for all project names, and aligns display titles with the SiSDK / GSDK example-app naming effort.

Directory structure — examples are organized under multiprotocol_app/ by protocol combination (ot-ble/, zb-ble/, zb-ot/, zb-ot-ble/), then by architecture (soc/, ncp/, ncp-rcp/, rcp/). UART / SPI transport variants share a subdirectory; minimal variants share a subdirectory with their base sample.

project_name / path renames (21 applications):

  • OpenThread + BLE (ot-ble/): ot-ble-dmp → mp-ot-ble-soc; ot-ble-dmp-no-buttons → mp-ot-ble-soc-minimal; ot-ble-dmp-tz-ns → mp-ot-ble-soc-tz; ot-ble-dmp-multi-instance → mp-ot-ble-soc-multi-instance; ot-ncp-ftd-ble-rcp → mp-ot-ncp-ble-rcp.

  • Zigbee + BLE (zb-ble/): zigbee_ble_dynamic_multiprotocol_light → mp-zb-ble-soc-light (plus -minimal, -sed, -sed-minimal variants); zigbee_ble_direct_device_light → mp-zb-ble-soc-zdd-light; zigbee_ncp-ble_ncp-uart/spi → mp-zb-ble-ncp-uart/spi.

  • Zigbee + OpenThread (zb-ot/): z3-light_ot-ftd_soc → mp-zb-ot-soc-light; zigbee_ncp-ot_rcp-uart/spi → mp-zb-ncp-ot-rcp-uart/spi; zigbee_ncp_ot_rcp_uart_gp_multi_rail → mp-zb-ncp-ot-rcp-uart-gp.

  • Zigbee + OpenThread + BLE (zb-ot-ble/): zigbee_ncp-ot_rcp-ble_rcp-uart/spi → mp-zb-ncp-ot-rcp-ble-rcp-uart/spi; rcp-uart/spi-802154-blehci → mp-zb-ot-ble-rcp-uart/spi.

Label updates — display titles now follow a consistent pattern: protocol names spelled out, architecture and transport where applicable, and explicit protocol-role coupling for mixed-role co-processor apps (e.g. "Zigbee NCP + OpenThread RCP - UART (CMP)" instead of legacy titles such as "Zigbee - NCP + OpenThread - RCP …" or "Multiprotocol (OpenThread+Zigbee+BLE) - RCP (SPI)"). DMP (Dynamic Multiprotocol) and CMP (Concurrent Multiprotocol) are noted in labels or descriptions where relevant.

Naming convention — all project names use the mp-{protocols}-{arch}[-{transport}][-{usecase}][-{variant}] pattern with hyphens throughout; protocols are ordered Zigbee, OpenThread, then BLE; mixed-role co-processor apps couple each protocol to its role (e.g. mp-zb-ncp-ot-rcp-uart).

Multiprotocol package reorganization#

The file paths of components and applications inside multiprotocol packages have been re-organized to give those packages a more cohesive file structure. This should not affect how the content is displayed in Simplicity Studio.

Removed Features#

None.

Deprecated Features#

None.

API Changes#

New APIs | Modified APIs | Removed APIs | Deprecated APIs

New APIs#

None.

Modified APIs#

None.

Removed APIs#

Removed in 9.1.0#

Removed API Name

Was Deprecated?

sl_802154_radio_set_scheduler_priorities

Yes

Deprecated APIs#

None.

Bug Fixes#

Fixed in 9.1.0#

ID Issue Description GitHub / Salesforce Reference (if any) Affected Software Variants, Hardware, Modes, Host Interfaces
1569320 Fixed an issue where CPCd could crash after a BLE scan with an active OT network in the mp-ot-ncp-ble-rcp application. Updated SL_BTCTRL_RTOS_LINK_LAYER_TASK_STACK_SIZE to 1100 for Series 2 devices. Note: RTOS stack sizes require tuning as needed. N/A mp-ot-ncp-ble-rcp app on Series 2 devices
1602054 Disabled the serial task on the OT-NCP + BLE-RCP application so that otbr-agent can start correctly with the mp-ot-ncp-ble-rcp application. N/A mp-ot-ncp-ble-rcp app
1613155 Fixed an issue where projects using the zigbee_stack_unix component and built with the "Copy all sources" option were missing certain header files, causing ZigbeeD make to fail with sl_token_manager_api.h: No such file or directory. SF: 00340128 ZigbeeD host builds with Copy All Sources
1619616 Fixed an intermittent failure when performing Update Trust Center Link Key in multi-hop scenarios, where the Trust Center could fail to handle the first Request Key (Trust Center Link Key) of the joining devices. N/A Zigbee + BLE DMP large-topology deployments
1628216 Fixed an issue where the Zigbee libraries for Android 12 were not being included in projects. All host architectures that the Zigbee libraries are built for currently use the toolchain_gcc SLC component. N/A ZigbeeD sample on Android 12
1639647 Fixed a CPC issue where the HCI Bridge could fail to start properly after a host reconnection to the remote device when using the mp-zb-ncp-ot-rcp-ble-rcp application. N/A CMP mp-zb-ncp-ot-rcp-ble-rcp app on MG24
1652601 Fixed an IPC issue affecting throughput testing with large packets (127 bytes) on the Zigbee Direct Device Light (ZDDLight) sample application. N/A Zigbee Direct Device Light app on DMP / CMP configurations

Fixed in Revision 1#

ID Issue Description GitHub / Salesforce Reference (if any) Affected Software Variants, Hardware, Modes, Host Interfaces
1569847 Fixed intermittent Bi-directional Green Power commissioning failures seen in CMP Zigbee NCP + OpenThread RCP scenarios under concurrent OpenThread traffic. N/A CMP Zigbee NCP + OpenThread RCP applications using Bi-directional Green Power
1591466 Fixed an issue where BLE GATT characteristic discovery did not return characteristic events when using zigbee_ble_dmp_cli after service discovery. N/A Zigbee + BLE DMP / CMP applications using zigbee_ble_dmp_cli
1651620 Fixed an issue in Simplicity Studio 6 where Zigbee ARM64 and related Linux-host components could be missing from Software Components for zigbeed and related host projects. N/A Zigbeed and other ARM Linux host projects in Simplicity Studio 6
1674274 Fixed an issue where mp-zb-ot-soc-light CMP could fail to start Zigbee on a different channel after OpenThread was already running with HDR PHY, fast channel switching (FCS), and RX duty cycling (DC). N/A CMP mp-zb-ot-soc-light app with HDR PHY + FCS + DC on BRD4407A / SiXG301
1693971 Fixed frequent CMP application crashes seen while creating an OpenThread network in HDR+DC+FCS+runtime PHY configurations. N/A mp-zb-ot-soc-light CMP app in HDR+DC+FCS runtime PHY configurations
1711599 Fixed an issue where zigbeed.conf was missing from multiprotocol_app in the 2026.6.0 SiSDK release. N/A zigbeed packaging in multiprotocol_app

Chip Enablement#

Added in 9.1.0#

None.

Application Example Changes#

New Examples | Modified Examples | Removed Examples | Deprecated Examples

New Examples#

Added in 9.1.0#

Example Name Description Supported Software Variants (if applicable) Supported Modes Supported OPNs / Boards / OPN Combinations Supported Host Interfaces

mp-zb-ncp-ot-rcp-ble-rcp-uart

mp-zb-ncp-ot-rcp-ble-rcp-spi

See readme in multiprotocol_app/zb-ot-ble/ncp-rcp/

 New Concurrent Multiprotocol (CMP) co-processor sample applications. Zigbee NCP, OpenThread RCP, and Bluetooth RCP run on one EFR device, multiplexed over CPC to a Linux host. Bluetooth is exposed as a BLE controller over CPC via bluetooth_hci_cpc, suitable for pairing with host-side CPC and a standard Bluetooth stack (i.e. BlueZ). N/A

NCP / RCP

All supported parts with sufficient RAM (≥ 128 KB)
  • CPC over UART
  • CPC over SPI

Modified Examples#

Modified in 9.1.0#

All Multiprotocol sample application project names, paths, and Simplicity Studio display titles have been standardized as part of the SiSDK / GSDK example-app naming effort. See the Standardized Multiprotocol sample application names enhancement above for the full list of renames, the new directory layout under multiprotocol_app/, and the unified mp-{protocols}-{arch}[-{transport}][-{usecase}][-{variant}] naming convention. Existing projects upgrading to 3.1.0 must be regenerated to pick up the new paths and project names.

Removed Examples#

None.

Deprecated Examples#

None.

Known Issues and Limitations#

ID Issue or Limitation Description GitHub / Salesforce Reference (if any) Workaround (if any) Affected Software Variants, Hardware, Modes, Host Interfaces
1209958 The Zigbee + OpenThread + BLE RCP may stop working in endurance testing (~2 hours) on MG24 and MG21 devices with constant and concurrent traffic on all three stacks. N/A None Zigbee + OpenThread + BLE RCP app
1385052 Coex-enabled RCP may still occasionally transmit TX ACK after losing the Grant even when Acking is disabled and TX Abort is enabled. N/A This will be fixed in future releases. Coex-enabled RCP
1385486 TX from coex-enabled RCP may infrequently happen without the request after turning on the non-802.15.4 compliant MAC Holdoff coex option. N/A This will be fixed in future releases. Coex-enabled RCP
1639512 In the Z3GatewayCPC host with the mp-zb-ncp-ot-rcp-ble-rcp use case, Z3GatewayCPC may crash if Zigbee and BLE protocols are under heavy load and OTBR is restarted. N/A This will be fixed in a future release. CMP mp-zb-ncp-ot-rcp-ble-rcp app on MG24 (BRD4187C / BRD4186C)