WiSeConnect - SiWx91x Bluetooth LE SDK Version 4.0.0 (Jan 22, 2026) - Release Notes#
Wi-Fi 6 + BLE (WiSeConnect) SDK Version 4.0.0
Simplicity SDK Version 2025.12.0
The SiWx91x Bluetooth LE Software Development Kit (SDK) provides feature-rich Bluetooth 5 connectivity with multi-connection capabilities, advanced advertising extensions, and power optimization for diverse IoT applications.
Click here for earlier releases.
Release Summary#
Key Features | API Changes | Bug Fixes | Chip Enablement
Key Features#
None
API Changes#
None
Bug Fixes#
Multiple BLE issues were resolved, including legacy pairing, asynchronous attribute-value handling, incorrect passkey generation, and the WLAN Power Save Disable API.
Stability and performance improvements were made by fixing DUT hang conditions, TX notification delays with 10 BLE connections, and issues in dense environments for multi-connection applications.
Additional updates include removing unsupported KCC values, fixing the unused NUM_PKTS macro, and resolving local ATT-value failures with variable-length characteristics.
Chip Enablement#
None
Key Features#
New Features | Enhancements | Removed Features | Deprecated Features
Note: See Feature Matrix for a list of any applicable APIs, examples, software variants, modes, hardware, and host interfaces applicable for each feature.
New Features#
None
Enhancements#
Reduced active time during extended advertising events to improve power efficiency and performance.
Updated BLE synchronous and Asynchronous APIs descriptions for improved clarity and accuracy.
Updated the description of the SL_SI91X_BT_BLE_STACK_BYPASS_ENABLE macro to clarify that it should only be used with Zephyr.
Added additional documentation notes for the RSI_BLE_NUM_REC_BYTES macro in the
ble_custom_ext_feature_bit_mapconfiguration to clarify its usage and behavior.Replaced legacy UART APIs with Silicon Labs UART APIs in
bt_stack_bypassapp.
Removed Features#
None
Deprecated Features#
None
API Changes#
New APIs | Modified APIs | Removed APIs | Deprecated APIs
New APIs#
Added rsi_ble_acceptlist_on_type API to set the acceptlist filter based on advertising data type, length, and value.
Modified APIs#
None
Removed APIs#
None
Deprecated APIs#
None
Bug Fixes#
Note: See the Feature Matrix section for a list of all hardware parts that work with the WiSeConnect SDK.
| ID | Issue or Limitation Description | GitHub / Salesforce Reference (if any) | Workaround (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|---|
| 1543604 | Fixed a BLE connection timeout (0x4E08) issue during simultaneous bidirectional TX/RX data transfers of 230 bytes across 10 BLE connections. | None | None |
|
| 1514763 |
Fixed an issue where BLE legacy pairing failed when the DUT was configured with the 'Keyboard Display' IO capability and the NRF dongle was set to Display YesNo.
|
None | None |
|
| 1509492 |
Fixed an issue where rsi_ble_set_att_value_async API fails with a 0x4E60 (Invalid Handle Range) error code when performing connect, disconnect, and reconnection tests with glucose applications.
|
None | None |
|
| 1497730 | Resolved DUT hang occurring after approximately 6 hours during repeated peripheral connect/disconnect cycles while performing TX/RX notifications with 10 BLE connections. | None | None |
|
| 1496803 | Fixed an issue where the device delayed TX notifications to a central device by approximately 40-50 seconds when performing simultaneous bidirectional data transfers (TX/RX) with 10 BLE connections. | None | None |
|
| 1465165 |
Fixed an issue where the device incorrectly generated a passkey during BLE pairing when the initiator (DUT) I/O capability was configured as Keyboard Display and the responder as Display Only.
|
None | None |
|
| 1516085 |
Replaced legacy UART API with Silicon Labs UART APIs in the bt_stack_bypass application.
|
None | None |
|
| 1505006 | Removed KCC region values from the BLE IC max power regulatory tables as the devices are not tested for KCC compliance. | None | None |
|
| 1516551 | Fixed an issue where the NUM_PKTS macro was defined but not used in the BLE PER application. | None | None |
|
| 1506132 |
Fixed an issue where the rsi_ble_set_local_att_value API returned error code 0x4046 when services were maintained in firmware with the VARIABLE_LENGTH_CHARACTERISTICS feature.
|
None | None |
|
| 1463443 |
Fixed an issue where the WLAN Power Save Disable API failed to disable power save mode in the ble_secureconnection_psram application.
|
None | None |
|
| 1488482 | Fixed a hang issue that occurred while processing the connection parameter update response command during testing with 10 BLE connections using an encrypted image with both TA and M4 power-save modes enabled. | None | None |
|
Chip Enablement#
None
Application Example Changes#
New Examples | Modified Examples | Removed Examples | Deprecated Examples
Note: See the Feature Matrix section for a list of all hardware parts that work with the WiSeConnect SDK.
New Examples#
None
Modified Examples#
None
Removed Examples#
None
Deprecated Examples#
None
Known Issues and Limitations#
Note: See the Feature Matrix section for a list of all hardware parts that work with the WiSeConnect SDK.
| ID | Issue or Limitation Description | GitHub / Salesforce Reference (if any) | Workaround (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|---|
| 1504605 | For ICs, customers must obtain certification for the required regions. After certification, the corresponding values are loaded through the "BLE – Update Gain Table" APIs. | None | None |
|
| 1458618 |
The ble_data_length application example does not work with 121x and 141x PSRAM OPNs.
|
None | None |
|
| 1465175 | The SiWx917 device hangs when power-save mode is enabled during BLE transmit and receive (TX/RX) notifications using the HP chain. | None | None |
|
| 1371967 | BLE anchor points were missing during packet exchanges with the PTS dongle when the connection interval (CI) exceeded 960 ms and the supervision latency (SL) was set to 5. | None | None |
|
| 1523829 | The minimum supported BLE GATT capability is limited to 4 services and 20 attributes for all memory configurations. | None | None |
|
| 1567221 | The output transmit power on the BLE HP chain may be higher in end-to-end mode compared to PER test mode across temperatures. | None | None |
|
| N/A | The BLE secondary latency value is valid only up to 32. | None | None |
|
| N/A | Maximum supported AE data length is 200 bytes. | None | None |
|
| N/A |
Supports only two ADV_EXT sets.
|
None | None |
|
| N/A | Supports only two simultaneous BLE connections (either two peripheral, two central, or one central and one peripheral) when Advertising Extensions are enabled. | None | None |
|
| N/A | System-level changes introduced to enhance stability have resulted in some increase in power numbers (up to 15% for smaller connection interval of 200 ms) for BLE connected only cases for modules only. Impact is smaller for longer connection intervals. | None | None |
|
| 1574418 |
Using slc generate --toolchain gcc or slc generate --with toolchain_gcc might fail with exclusivity errors due to the wiseconnect_toolchain_gcc_standard component incorrectly providing toolchain_gcc, resulting in a conflict with the SiSDK toolchain_gcc component. If using those two command line options results in exclusivity errors, then you can remove them. Note that in a future WiseConnect release, you might have to reintroduce the toolchain option on the command line. Refer to future WiseConnect release notes for updates on possible behavior changes.
|
None | None |
|