Bluetooth LE SDK Version 10.1.1 (September 24, 2025) - Release Notes#
Simplicity SDK Version 2025.6.2
The Bluetooth SDK is an advanced Bluetooth 6.0-compliant stack that provides all of the core functionality along with multiple API to simplify development. The core functionality offers both standalone mode, allowing a developer to create and run their application directly on the SoC, and NCP mode, allowing for the use of an external host MCU.
Click here for earlier releases.
Release Summary#
Key Features | API Changes | Bug Fixes | Chip Enablement
Key Features#
Added in 10.1.0#
None.
Added in 10.0.0#
Optimized Bluetooth task scheduling. PAWR scheduling component is not needed anymore and will be deprecated in future.
Added a vendor specific command to get channel assessment information from Link Layer.
Added support for Bluetooth channel classification feature.
API Changes#
Changed in 10.1.1#
PA mode is now app-configurable via
SL_BT_CONTROLLER_PA_CONFIG.
Changed in 10.1.0#
None.
Changed in 10.0.0#
Changed priority configuration in Bluetooth Host (Stack).
Added peripheral channel classification changed HCI event.
Added HCI event when PAWR parameters are changed by new PAWR Interval change feature.
Bug Fixes#
Fixed in 10.1.1#
Improved Link Layer scheduling: correct anchor selection, fairness, and scan-window handling.
PAwR robustness: empty-center scheduling, correct skipped subevent reporting, stricter subevent validation.
xG21 (MG21): Restored 80 MHz system clock requirement to prevent BLE advertising/connection failures on custom boards.
Fixed in 10.1.0#
None.
Fixed in 10.0.0#
Vendor specific HCI events used wrong event code.
Periodic advertisement issues.
Interrupt priorities in single protocol Bluetooth with RTOS.
Connection establishment issue with extended advertising.
Chip Enablement#
None.
Key Features#
New Features | Enhancements | Removed Features | Deprecated Features
New Features#
Added in 10.1.0#
Alpha quality release of Periodic Advertising Synchronization Transfer (PAST) over Periodic Advertising with Responses (PAwR)
Added in 10.0.0#
Added a new Bluetooth Component Channel Classification as experimental feature. Feature currently only supports HCI/RCP interface. This component implements the Channel classification feature defined in Bluetooth specification. This initial implementation automatically enables the Channel reporting once connected. Channel reports are delivered by vendor specific events; it is up to the upper stack to handle the reports and update the controller channel map.
Added vendor specific feature PAwR Interval Change to allow changing interval of Periodic Advertisement with Responses.
Added vendor specific feature to read current channel assesment information from the Bluetooth controller.
Enhancements#
Added in 10.1.1#
Bluetooth LE Controller now honors an application-configurable PA mode and no longer forces a default that can lead to selecting the high-power PA. This restores expected behavior and allows choosing low-power PA where needed. Applications should use the provided configuration option to set their desired PA mode.
Added in 10.1.0#
None.
Added in 10.0.0#
Optimized Bluetooth task scheduling. PAWR scheduling component is not needed anymore and will be deprecated in future. Default scheduler is smart enough to properly schedule multiple connections to interleave with PAwR advertisements.
Allow starting multiple Channel Sounding procedures simultaneously. New Channel sounding procedures will be queued and started once previous completes.
Removed Features#
Removed in 10.1.0#
None.
Removed in 10.0.0#
Removed Feature | Was Deprecated? |
|---|---|
Removal of the BLE support for Amazon AWS IoT | Yes |
Deprecated Features#
None.
API Changes#
New APIs | Modified APIs | Removed APIs | Deprecated APIs
New APIs#
Added in 10.1.0#
None.
Added in 10.0.0#
New API Signature | Deprecated API replaced by this (if any) |
|---|---|
HCI Event vs_silabs_channel_classification: reported when channel classification is received from remote peripheral device | |
HCI Event vs_siliconlabs_periodic_advertising_sync_transfer_received: reported when PAWR parameters are changed by new PAWR Interval change feature | |
HCI Command vs_siliconlabs_periodic_advertising_set_info_transfer: Transfer the synchronization information of an advertising set that is actively performing periodic advertising. The transfer happens over a Periodic Advertising with Responses (PAwR) train. | |
HCI Command vs_siliconlabs_change_periodic_advertising_parameters: Use this command to change the parameters of an active PAwR advertising train. |
Modified APIs#
Modified in 10.1.0#
None.
Modified in 10.0.0#
Old API | Modified |
|---|---|
Priority configuration in Bluetooth Host (Stack) | The Link Layer scheduler priority configuration has been added to the Bluetooth Low Energy Controller component. |
Removed APIs#
None.
Deprecated APIs#
Deprecated in 10.1.0#
None.
Deprecated in 10.0.0#
Deprecated API Name | Planned Removal Date |
|---|---|
sl_btctrl_filter_scan_request_transmission_cb | 2026 Q2 |
The Link Layer scheduler priority configuration in the Bluetooth Host (Stack) component has been deprecated. | 2026 Q2 |
Bug Fixes#
Fixed in 10.1.1#
| ID | Issue Description | GitHub / Salesforce Reference (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|
| 1506571 | Fixed a Bluetooth Link Layer scheduling mix-up that could select the wrong anchor-point strategy. The deprecated the legacy even-connection scheduler, and PAwR connection scheduler use the correct even scheduling and empty-center scheduling, respectively. This improves connection timing and reliability. | None | All; generic software issue |
| 1498088 | Fixed a PAwR synchronization issue where skipped subevent transmissions during connection creation were not reported to the host, which could cause confusion on Bluetooth host's side. The controller now reports skipped subevents correctly to keep host and controller aligned. | None | All; generic software issue |
| 1472068 | Improved BLE Link Layer scheduling and PAwR robustness. Fixed rare cases where lower-priority activities could delay PAwR or connection events, corrected scan window handling during connection creation, and tightened validation of PAwR subevent data from the host. Resolves missing AUX_SYNC_SUBEVENT_IND indications under mixed advertising and scanning loads. | None | All; generic software issue |
| 1401692 | Resolved an issue where BLE advertising/connection could fail on MG21 custom boards when using SDK 2024.12 and later, due to an incorrect default system clock configuration. The platform now restores the proper 80 MHz system clock requirement for Bluetooth on xG21. Customers on affected releases should configure the system clock to HFRCODPLL at 80 MHz. | None | EFR32xG21 (MG21) custom boards |
Fixed in 10.1.0#
None.
Fixed in 10.0.0#
| ID | Issue Description | GitHub / Salesforce Reference (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|
| 1409280 | Fixed issue where vendor specific HCI Events used wrong event code. Now all vendor specific events use event code 0xFF. Old behavior can be enabled with SL_BT_CONTROLLER_USE_LEGACY_VENDOR_SPECIFIC_EVENT_CODE flag in Bluetooth controller configuration. | None | HCI / RCP interface only |
| 1381141 | Multiple connections with periodic advertisement with responses scheduling conflicts has been fixed. | None | All; generic software issue |
| 1378000 | Periodic advertisement with responses scheduling issues with simultaneous scanner has been fixed. | None | All; generic software issue |
| 1373310 | Fixed issues where interrupt priorities were not properly configured with RTOS in SOC/NCP mode. This affects single protocol mode. | None | RTOS and SOC/NCP |
| 1311673 | Fixed a rare issue in connection establishment on secondary channel where device might get stuck. | None | All; generic software issue |
Known Issues and Limitations#
None.