WiSeConnect - SiWx91x Bluetooth LE SDK Version 4.1.1 (Jul 29, 2026) - Release Notes#

Wi-Fi 6 + BLE (WiSeConnect) SDK Version 4.1.1

Simplicity SDK Version 2026.6.1

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.

See WiSeConnect releases for earlier releases.

Release Summary#

Key Features | API Changes | Bug Fixes | Chip Enablement

Key Features#

Added in 4.1.1#

None

Added in 4.1.0#

  • Added support for dynamically enabling or disabling BLE.

  • Added logging support for BLE.

  • Added RC clock support for BLE.

  • Added support for BLE stack bypass/offloading.

  • Added support for BLE-based firmware over-the-air (OTA) updates from a remote central device.

  • Added support for BLE operation when the low-power bit is disabled.

API Changes#

Added in 4.1.1#

None

Added in 4.1.0#

  • Created API to set minimum encryption key size for SMP pairing.

  • Added API to disable BLE at runtime.

  • Added API to enable BLE at runtime.

  • Added API to register common GATT callbacks.

  • Added API to register GATT server callbacks.

  • Added API to register GATT client callbacks.

Bug Fixes#

Fixed in 4.1.1#

  • Updated Keyboard Display IO capability documentation for BLE SMP.

  • Fixed an issue where a second extended central connection could fail when another bonded extended central connection was already active.

  • Fixed an issue in LE extended connections where initiating a central connection could fail while a bonded peripheral connection was already active, due to incorrect peer address resolution.

  • Fixed an issue where, after bonding, the DUT sent another SMP request instead of initiating encryption when a remote central attempted to reconnect.

  • Fixed AE connection issue in coded PHY when DUT is purely controller with bt_stack_bypass application.

  • Updated default log level as "INFO" for all the BLE NCP examples.

Fixed in 4.1.0#

  • Fixed a BLE re-pairing attack vulnerability by adding the rsi_ble_vendor_set_SMP_min_enc_keysize API to set the minimum encryption key size (7 - 16).

  • Fixed an issue where the DUT became unresponsive during BLE TX/RX notifications with power save mode enabled on the 121x board using the ble_unified_ae_coex_app_soc application.

  • Fixed an issue where BLE PER was not working when the NWP watchdog timer was enabled.

  • Fixed an issue where the DUT stopped responding when power-save mode was enabled during BLE (TX/RX) notifications using the HP chain.

  • Fixed an issue where the DUT responds with ATT_ERROR_RESP to ATT_WRITE_REQ packets over the air when the mobile writes data with variable length enabled.

  • Replaced hardcoded values (magic numbers) with well-defined macros in BLE files to improve code readability and maintainability.

  • Fixed spelling and typographical issues across BLE components and example files.

  • Fixed a security vulnerability regarding attribute permission levels for the characteristic value declaration and the CCCD.

  • Fixed an issue where the ble_data_length application example did not work with 121x and 141x PSRAM OPNs.

  • Fixed an issue in the Extended Create Connection command where the initiator address was set to zeros when own_addr_type was configured to a resolvable random address.

Chip Enablement#

Added in 4.1.1#

None

Added in 4.1.0#

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#

Added in 4.1.1#

None

Added in 4.1.0#

  • Added support for dynamically enabling or disabling BLE.

  • Added logging support for BLE.

  • Added RC clock support for BLE.

  • Added support for BLE stack bypass/offloading.

  • Added support for BLE-based firmware over-the-air (OTA) updates from a remote central device.

  • Added support for BLE operation even when the low-power bit is disabled.

Enhancements#

Added in 4.1.1#

  • Updated default log level as "INFO" for all the BLE NCP examples.

  • Updated Refresh Module details in the BLE example READMEs.

Added in 4.1.0#

  • Replaced BLE synchronous APIs with corresponding asynchronous APIs in all applications.

Removed Features#

Removed in 4.1.1#

None

Removed in 4.1.0#

None

Deprecated Features#

Deprecated in 4.1.1#

None

Deprecated in 4.1.0#

None

API Changes#

New APIs | Modified APIs | Removed APIs | Deprecated APIs

New APIs#

Added in 4.1.1#

None

Added in 4.1.0#

New API Signature

Deprecated API replaced by this (if any)

int32_t rsi_ble_vendor_set_SMP_min_enc_keysize (uint8_t min_keysize)

None

int32_t rsi_ble_disable (void)

None

int32_t rsi_ble_enable (void)

None

void rsi_ble_gatt_common_register_callbacks (rsi_ble_on_gatt_write_event_t ble_on_gatt_event)

None

void rsi_ble_gatt_server_register_callbacks (...)

None

void rsi_ble_gatt_client_register_callbacks (rsi_ble_on_profiles_list_resp_t ble_on_profiles_list_resp, ...)

None

Modified APIs#

Modified in 4.1.1#

None

Modified in 4.1.0#

None

Removed APIs#

Removed in 4.1.1#

None

Removed in 4.1.0#

None

Deprecated APIs#

Deprecated in 4.1.1#

None

Deprecated in 4.1.0#

None

Bug Fixes#

Note: See the Feature Matrix section for a list of all hardware parts that work with the WiSeConnect SDK.

Fixed in 4.1.1#

ID Issue Description GitHub / Salesforce Reference (if any) Workaround (if any) Affected Software Variants, OPNs, Boards, Modes, Host Interfaces
1686948 Updated Keyboard Display IO capability documentation for BLE SMP. None None
  • Software variants: Standard and Lite
  • OPNs: All OPNs
  • Boards: All applicable boards
  • Modes: SoC, NCP
  • Host interfaces: N/A
1690504 Fixed an issue where a second extended central connection could fail when another bonded extended central connection was already active. None None
  • Software variants: Standard and Lite
  • OPNs: All OPNs
  • Boards: All applicable boards
  • Modes: SoC, NCP
  • Host interfaces: N/A
1690469, 1680025 Fixed an issue where a BLE extended central failed to establish a connection after connecting to a peripheral when the remote device used extended advertising. None None
  • Software variants: Standard and Lite
  • OPNs: All OPNs
  • Boards: All applicable boards
  • Modes: SoC, NCP
  • Host interfaces: N/A
1715568 Fixed an issue where, after bonding, the DUT sent another SMP request instead of initiating encryption when a remote central attempted to reconnect. None None
  • Software variants: Standard and Lite
  • OPNs: All OPNs
  • Boards: All applicable boards
  • Modes: SoC, NCP
  • Host interfaces: N/A
1682690 Fixed AE connection issue in coded PHY when DUT is purely controller with bt_stack_bypass application. None None
  • Software variants: Standard and Lite
  • OPNs: All OPNs
  • Boards: All applicable boards
  • Modes: SoC, NCP
  • Host interfaces: N/A
1673596 Updated default log level as "INFO" for all the BLE NCP examples. None None
  • Software variants: Standard and Lite
  • OPNs: All OPNs
  • Boards: All applicable boards
  • Modes: SoC, NCP
  • Host interfaces: N/A

Fixed in 4.1.0#

ID Issue Description GitHub / Salesforce Reference (if any) Workaround (if any) Affected Software Variants, OPNs, Boards, Modes, Host Interfaces
1599776 Fixed an issue where the DUT became unresponsive during BLE TX/RX notifications with power save mode enabled on the 121x board using the ble_unified_ae_coex_app_soc application. None None
  • Software variants: Standard and Lite
  • OPNs: 121x and 141x PSRAM OPNs
  • Boards: All applicable boards
  • Modes: SoC
  • Host interfaces: N/A
1587091 Fixed an issue where BLE PER did not work when the NWP watchdog timer was enabled. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1465175 Fixed an issue where the DUT device stopped responding when power-save mode was enabled during BLE transmit and receive (TX/RX) notifications using the HP chain. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1447917 Fixed an issue where the DUT responds with ATT_ERROR_RESP to ATT_WRITE_REQ packets over the air when a mobile device wrote data with variable length enabled. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1613489 Replaced hardcoded values (magic numbers) with well-defined macros in BLE files to improve code readability and maintainability. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1608196 Fixed spelling and typographical issues across BLE components and all example files. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1592951 Fixed a security vulnerability related to attribute permission levels for the characteristic value declaration and CCCD. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1458618 Fixed an issue where the ble_data_length application example did not work with 121x and 141x PSRAM OPNs. None None
  • Software variants: Standard and Lite
  • OPNs: 121x and 141x PSRAM
  • Boards: All applicable boards
  • Modes: SoC
  • Host interfaces: N/A
1354933 Fixed the BLE re-pairing attack vulnerability by adding the rsi_ble_vendor_set_SMP_min_enc_keysize API to set the minimum encryption key size (7–16). None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1638794 Fixed an issue in the Extended Create Connection command where the initiator address was set to zeros when own_addr_type was configured to a resolvable random address. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC
  • Host interfaces: N/A

Chip Enablement#

Added in 4.1.1#

None

Added in 4.1.0#

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#

Added in 4.1.1#

None

Added in 4.1.0#

Example Name

Description

Supported Software Variants (if applicable)

Supported Modes

Supported OPNs / Boards / OPN Combinations

Supported Host Interfaces

BLE - FW OTA Upgrade (See README)

Demonstrates how to update the SiWx91x module firmware over-the-air (OTA) by receiving a firmware image from a remote BLE central (e.g., smartphone or PC tool).

Standard and Lite

SoC, NCP

OPNs: All, Boards: All

SPI, UART

Modified Examples#

Modified in 4.1.1#

None

Modified in 4.1.0#

Example Name

Description

Supported Software Variants (if applicable)

Supported Modes

Supported OPNs / Boards / OPN Combinations

Supported Host Interfaces

BLE - BT Stack Bypass (See README)

Demonstrates how to configure Raw HCI commands through UART, allowing the BLE stack to be bypassed or offloaded in SoC and NCP modes.

Standard and Lite

SoC, NCP

OPNs: All, Boards: All

SPI

All BLE Applications

Replaced standard printf with SL_DEBUG_LOG_V2 prints in all BLE applications.

Standard and Lite

SoC, NCP

OPNs: All, Boards: All

SPI, UART

Removed Examples#

Removed in 4.1.1#

None

Removed in 4.1.0#

None

Deprecated Examples#

Deprecated in 4.1.1#

None

Deprecated in 4.1.0#

None

Known Issues and Limitations#

Note: See the Feature Matrix section for a list of all hardware parts that work with the WiSeConnect SDK.

Added in 4.1.1#

None

Added in 4.1.0#

ID Issue or Limitation Description GitHub / Salesforce Reference (if any) Workaround (if any) Affected Software Variants, OPNs, Boards, Modes, Host Interfaces
1567221 BLE connected power consumption is increased after the transmit power alignment fix. The increase is approximately 8% at the 200 ms connection interval and approximately 29% at the 1.28 sec connection interval. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
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
  • Software variants: Standard and Lite
  • OPNs: All except SiW917Y1GN and SiW917Y1GA modules
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1371967 BLE anchor points were missing during packet exchanges with the PTS dongle when the Connection Interval (CI) exceeded 960 ms and the Peripheral Latency (SL) was set to 5. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1523829 The minimum supported BLE GATT capability is limited to 4 services and 20 attributes for all memory configurations. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC
  • Host interfaces: N/A
N/A The BLE secondary latency value is valid only up to 32. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
N/A The maximum supported AE data length is 200 bytes. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
N/A Supports only two ADV_EXT sets. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
N/A When advertising extensions are enabled, they support only two simultaneous BLE connections: either two peripheral, two central, or one central and one peripheral. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
N/A System-level changes introduced to enhance stability have resulted in some increase in power consumption (up to 15% for shorter connections interval, e.g., 200 ms) for modules only cases. However, the impact is smaller for longer connection intervals. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
1574418 Using slc generate --toolchain gcc or slc generate --with toolchain_gcc may result in component exclusivity errors due to a conflict between the WiseConnect wiseconnect_toolchain_gcc_standard component and the Simplicity SDK toolchain_gcc component. If these errors occur, generate the project without the toolchain option. Future WiseConnect releases may require reintroducing the toolchain option; refer to upcoming release notes for any changes. None If you encounter the exclusivity errors, remove the command line option.
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
N/A BLE power consumption is higher when using the RC clock compared to the XTAL clock. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
N/A BLE power consumption may increase by approximately 20% to 50% when the Low Power bit is disabled. The impact is higher for smaller connection intervals, such as 200 ms, and lower for longer connection intervals. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART
N/A When DEBUG or INFO logging is enabled, SMP passkey entry is supported only with the SL Log Si91x Backend Iostream Compact with RTT backend. Enabling RTT prevents the M4 from entering power save mode. In addition, using the SL Log Backend UART might prevent the SMP passkey from being displayed correctly in host logs. None None
  • Software variants: Standard and Lite
  • OPNs: All
  • Boards: All
  • Modes: SoC, NCP
  • Host interfaces: SPI, UART