Bluetooth Mesh SDK Version 9.0.1 (July 21, 2025) - Release Notes#

Simplicity SDK Version 2025.6.1

Bluetooth Mesh is a standards-based, many-to-many communication topology available for Bluetooth Low Energy (LE) devices, optimized for large-scale networks and ideally suited for building automation, sensor networks, and asset tracking.

Click here for earlier releases.

Release Summary#

Key Features | API Changes | Bug Fixes | Chip Enablement

Key Features#

Added in 9.0.1#

None.

Added in 9.0.0#

Node firmware can now be updated without having to reprovsion the node.
Multiple bug fixes and quality improvements

API Changes#

Added in 9.0.1#

None.

Added in 9.0.0#

Added API for controlling BLOB transfer and firmware update message sending cadence.
Added API for switching to a more robust BLOB transfer server interface.

Bug Fixes#

Fixed in 9.0.1#

None.

Fixed in 9.0.0#

Corrected a number of BLOB transfer and firmware update issues.
Corrected a number of generic, lighting, and LC model issues.
Fixed embedded provisioner migration from old SDK versions

Chip Enablement#

None.

Key Features#

New Features | Enhancements | Removed Features | Deprecated Features

New Features#

Added in 9.0.1#

Node firmware can now be updated without having to reprovsion the node. The new formatting of model configuration data allows models and elements on the node to be changed as a result of a firmware update without having to reprovision the device (although a Node Address Refresh procedure or a Node Composition Refresh procedure may still be required). Note that projects that make use of the old formatting of model configuration data must first migrate to use the new format.

Added in 9.0.0#

Improved formatting of model configuration data that is stored on the device.

Enhancements#

Added in 9.0.1#

None.

Added in 9.0.0#

Improved formatting of model configuration data that is stored on the device, using model storage component version 2, is now the default; the new format provides more flexibility for project structure changes. Projects using the legacy model storage must first be converted to use the new storage. A migration component is provided to help in the conversion.

Removed Features#

None.

Deprecated Features#

None.

API Changes#

New APIs | Modified APIs | Removed APIs | Deprecated APIs

New APIs#

Added in 9.0.1#


New API Signature	Deprecated API replaced by this (if any)
sl_status_t sl_btmesh_fw_dist_server_configure_throttle	N/A
sl_status_t sl_btmesh_fw_standalone_updater_configure_throttle	N/A
sl_status_t sl_btmesh_mbt_client_configure_throttle	N/A
sl_status_t sl_btmesh_mbt_server_block_start_rsp	N/A
sl_status_t sl_btmesh_mbt_server_enable_block_start_req	N/A

Added in 9.0.0#


New API Signature	Deprecated API replaced by this (if any)
sl_status_t sl_btmesh_model_migration_migrate_models	N/A
sl_status_t sl_btmesh_node_compare_dcd	N/A
sl_status_t sl_btmesh_scene_client_deinit	N/A
sl_status_t sl_btmesh_scene_setup_server_deinit	N/A

Modified APIs#

Added in 9.0.1#

None.

Added in 9.0.0#


Old API	Modified
sl_status_t sl_btmesh_proxy_send_solicitation(uint8_t netkey_index, uint16_t element_index, uint16_t dst)	sl_status_t sl_btmesh_proxy_send_solicitation(uint16_t netkey_index, uint16_t element_index, uint16_t dst)
sl_status_t sl_btmesh_remote_provisioning_client_open_link(uint16_t enc_netkey_index, uint16_t server, uint16_t elem_index, uint16_t timeout_sec, uint8_t dkri, uuid_128 uuid)	sl_status_t sl_btmesh_remote_provisioning_client_open_link(uint16_t enc_netkey_index, uint16_t server, uint16_t elem_index, uint16_t timeout_sec, enum sl_btmesh_remote_provisioning_client_nppi_operation_t dkri, uuid_128 uuid)

Removed APIs#

Removed in 9.0.1#

None.

Removed in 9.0.0#


Removed API Name	Was Deprecated?
sl_btmesh_prov_test_identity	Yes
sl_btmesh_test_set_adv_scan_params	Yes
sl_btmesh_test_set_segment_send_delay	Yes
sl_btmesh_test_set_sar_config	Yes

Deprecated APIs#

Deprecated in 9.0.1#

None.

Deprecated in 9.0.0#


Deprecated API Name	Planned Removal Date
sl_btmesh_node_get_networks	Dec 2025

Bug Fixes#

Fixed in 9.0.1#

ID	Issue Description	GitHub / Salesforce Reference (if any)	Affected Software Variants, Hardware, Modes, Host Interfaces
1412121	Allow more than one Scheduler Server model.	None	All; generic software issue
1413864, 1425025, 1451316, 1452212, 1452213	Multiple fixes and improvements to make Firnware Update model operation more robust in a high-load environment.	325400	All; generic software issue
1427300	Correct Mesh BLOB Transfer Server model pull mode transfers completion	None	All; generic software issue
1434214	DFU distributor server message sending corrected to handle all values of SL_BTMESH_CONFIG_APP_TXQ_SIZE correctly	None	All; generic software issue
1449127	Fix regressions with CTL, HSL, and LC model handling of power on/off state, and state transitions in general	None	All; generic software issue
1453059, 1455793	Fix regression with Generic Level Move and Generic Level Delta handing when reacing min/max values	None	All; generic software issue
1455257	Return at most 255 bytes of statistics data even if more are requested by application.	329287	All; generic software issue
1456316	Corrected the use of device composition page 1 when a device has received a firmware update but has not yet begun a new term	None	All; generic software issue
1456429	Fixed issues with migrating an embedded provisioner from SDK version 1.x	329602	All; generic software issue
1457535	Optimized heap usage on MicriumOS.	None	MicriumOS; xG27 devices
1470416, 1473472	Corrected issues related to Mesh BLOB Transfer Server model timeout and state transition handling	None	All; generic software issue
1470419, 1470424	Fixed issues Mesh BLOB Transfer models and application communication, as well as Device Firmware Update models and application communication; unreliable event to the application caused issues in high load conditions.	None	All; generic software issue

Fixed in 9.0.0#

ID	Issue Description	GitHub / Salesforce Reference (if any)	Affected Software Variants, Hardware, Modes, Host Interfaces
1384577	Allow Device Composition Data state change during Node Address Refresh Procedure.	None	All; generic software issue
1406862	Fixed an unintended deactivation of LC mode when entering standby mode.	None	All; generic software issue
1412725	Corrected parameter value range for sl_btmesh_proxy_send_solicitation API call.	None	All; generic software issue
1439194, 1453067, 1453189	Fixed a number of issues in lighting and generic model state updates stemming from using generic level move operation.	327432	All; generic software issue
1442415	Close remote provisioning link only after Link Close message has been transmitted.	None	All; generic software issue
1449114	Corrected minor issues in Configuration Client BGAPI: Use the intended network key specified by enc_netkey_index to transmit sl_btmesh_config_client_get_model_pub() request; Do not allow removing the network key used to transmit sl_btmesh_client_remove_netkey() request as a response would not be sent after the removal; Corrected publication retransmission reporting	None	All; generic software issue
1450910	Properly handle provisioning bearer timeout during remote provisioning.	None	All; generic software issue
1451240	Send the correct device address during Node Composition Refresh procedure.	None	All; generic software issue
1451726	Fixed a problem in restoring generic model state on power up.	None	All; generic software issue
1426807	Fixed a problem in Bluetooth Mesh Sensor Client application which can be stuck in UART write loop.	None	All; generic software issue
1451726	Missing bootloader for btmesh_soc_nlc_basic_lightness_controller demo.	None	BRD2602A

Chip Enablement#

None.

Application Example Changes#

New Examples | Modified Examples | Removed Examples | Deprecated Examples

New Examples#

Added in 9.0.1#

None.

Added in 9.0.0#

Example Name	Description	Supported Software Variants (if applicable)	Supported Modes	Supported OPNs / Boards / OPN Combinations	Supported Host Interfaces
Bluetooth Mesh - NLC Energy Monitor.	An out-of-the-box Software Demo where the device acts as a mock Energy Monitor in a Networked Lighting Control (NLC) system.	Standard	SoC	All	None

Modified Examples#

Modified in 9.0.1#

None.

Modified in 9.0.0#

Example Name	Changes	Supported Software Variants if applicable	Supported Modes	Supported OPNs / Boards / OPN Combinations	Supported Host Interfaces
btmesh_host_dfu	The application allows firmware update without reprovisioning The fw_image_path is no longer a positional argument in the btmesh_host_dfu example	N/A	NCP	Boards: All External Hosts: PC	UART
All embedded examples	Migration from sl_system to sl_main as described here.	Standard	SoC	All	N/A

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
401550	No BGAPI event for segmented message handling failure.	212392, 214429, 216665	Application needs to deduce failure from timeout / lack of application layer response; for vendor models, an API has been provided.	All; generic software issue
454059	A large number of key refresh state change events are generated at the end of KR process, and that may flood NCP queue.	None	Increase NCP queue length in the project.	NCP interface; generic software issue
454061	Slight performance degradation compared to 1.5 in round-trip latency tests was observed.	None	None	All; generic software issue
624514	Issue with re-establishing connectable advertising if all connections have been active and GATT proxy is in use.	235615	Allocate one more connection than is needed.	All; generic software issue
841360	Poor performance of segmented message transmission over GATT bearer.	283876	Ensure that the underlying BLE connection’s Connection interval is short; ensure that ATT MTU is large enough to fit a full Mesh PDU; tune the minimum connection event length to allow multiple LL packets to be transmitted per connection event.	All; generic software issue
1204017	Distributor is not able to handle parallel self FW Update and FW Upload.	None	Don’t run self FW update and FW upload in parallel.	All; generic software issue
1226127	Host provisioner example can be stuck when it starts to provision a second node.	None	Restart the host provisioner app before provisioning the second node.	All; generic software issue