WiSeConnect - Network Stack Version 4.0.1 (Mar 25, 2026) - Release Notes#
Wi-Fi 6 + BLE (WiSeConnect) SDK Version 4.0.1
Simplicity SDK Version 2025.12.2
The Network Stack Software Development Kit (SDK) provides core and advanced networking features with Wi-Fi IoT cloud integration.
Click here for earlier releases.
Release Summary#
Key Features | API Changes | Bug Fixes | Chip Enablement
Key Features#
Added in 4.0.1#
Added Embedded MQTT password length support up to 512 bytes.
Added in 4.0.0#
Optimized LwIP timer management to improve performance and efficiency.
Added DNS Service Discovery (DNS-SD) support via mDNS for both IPv4 and IPv6.
API Changes#
Added in 4.0.1#
None
Added in 4.0.0#
Added new MQTT API to publish, subscribe, and manage MQTT connections directly from the network stack.
Bug Fixes#
Fixed in 4.0.1#
Addressed source MAC filtering for loopback packets in TCP/IP bypass mode.
Fixed mDNS discovery stability issues, including service discovery response and PTR events across iterations, start/stop reliability with multiple services, and discovery continuity during data transfer.
Fixed TLS data transfer stability in congested environments.
Resolved an issue where HTTP GET/POST requests were being initiated after an HTTP PUT request without calling reset_http_handles(). The DUT now correctly rejects such requests and returns error code 0x0015 as expected.
Fixed a DHCP handshake failure in concurrent mode with NAT+PAT enabled in congested environments.
Fixed in 4.0.0#
Resolved an issue where consecutive HTTPS requests (GET/PUT/POST) could fail due to incomplete socket cleanup.
Resolved HTTP server stability issues under congested network conditions.
Resolved remote termination issues occurring during socket open/close operations in a loop.
Resolved a DTLS synchronization issue that could interrupt data transmission and reception.
Resolved TLS data transfer stability issues in 352/320k mode when power save is enabled.
Chip Enablement#
Added in 4.0.1#
None
Added in 4.0.0#
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 4.0.1#
Added Embedded MQTT password length support up to 512 bytes.
Added in 4.0.0#
Added DHCP support from the host for IPv4 in Dual stack mode.
Added SNI extension support for Embedded MQTT.
Added NAT/PAT feature support.
Added DNS IP address support in AP mode.
Added support for Subject Name validation during TLS connections.
Added IPv6 support in Dual Stack mode.
Added DNS-SD support over mDNS for IPv4/IPv6.
Added adaptive timer optimizations in Hosted Network stack LWIP (IPv6 ND6, DHCP, DNS, ARP, ACD, TCP, MLD6) to improve power efficiency.
Enhancements#
Added in 4.0.1#
None
Added in 4.0.0#
None
Removed Features#
Removed in 4.0.1#
None
Removed in 4.0.0#
None
Deprecated Features#
Deprecated in 4.0.1#
None
Deprecated in 4.0.0#
None
API Changes#
New APIs | Modified APIs | Removed APIs | Deprecated APIs
New APIs#
Added in 4.0.1#
None
Added in 4.0.0#
New API Signature | Deprecated API replaced by this (if any) |
|---|---|
|
|
Modified APIs#
Modified in 4.0.1#
None
Modified in 4.0.0#
None
Removed APIs#
Removed in 4.0.1#
None
Removed in 4.0.0#
None
Deprecated APIs#
Deprecated in 4.0.1#
None
Deprecated in 4.0.0#
Deprecated API Name | Planned Removal Date |
|---|---|
2027-06 |
Bug Fixes#
Note: See the Feature Matrix section for a list of all hardware parts that work with the WiSeConnect SDK.
Fixed in 4.0.1#
| ID | Issue Description | GitHub / Salesforce Reference (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|
| 1580999 | Addressed source MAC filtering for loopback packets in TCP/IP bypass mode. | None |
|
| 1571398 | Fixed mDNS service discovery response and PTR events in multiple iterations. | None |
|
| 1571021 | Fixed mDNS discovery start/stop stability with multiple services. | None |
|
| 1571459 | Resolved firmware unresponsiveness during repeated mDNS init → register → discovery start → discovery stop loops. | None |
|
| 1571019 | Fixed mDNS discovery across iterations during data transfer. | None |
|
| 1427832 | Fixed TLS data transfer stability in congested environments. | None |
|
| 1581889 | Optimized IPv6 connectivity in lwip_ipv6_tcp_client example by refining power save mode handling. This addresses cases where IPv6 ping may not work from AP backend to DUT when using power save mode, restoring proper IPv6 network communication. | None |
|
| 1569583 | Enhanced IPv6 address handling in lwip_mqtt_over_tcp application. This resolves "invalid IPv6 address" errors and improves compatibility with both stateless and stateful IPv6 configurations, ensuring proper IPv6 address parsing and MQTT connectivity. | None |
|
| 1563253 | Optimized HTTP server client idle timeout to prevent hanging on slow or dead clients. This improves server reliability by automatically closing connections when clients connect but don't send data, preventing resource exhaustion and ensuring the server remains responsive. | None |
|
| 1556585 | Improved AWS MQTT connection handling after network rejoin. The device now automatically reconnects to the MQTT broker after successful network rejoin, eliminating the need for manual reconnection or reboot. | None |
|
| 1562633 | Optimized QoS1 PUBACK semaphore timeout from 572 seconds to 640 seconds. This improves MQTT publish reliability during extended operations in coex mode (WLAN+BLE), addressing cases where publish operations may stop after approximately 40 minutes of continuous operation. | None |
|
| 1611701 | Resolved an issue where HTTP GET/POST requests were initiated after an HTTP PUT request without calling reset_http_handles(). The DUT now correctly rejects such requests and returns error code 0x0015 as expected. | None |
|
| 1557787 | Fixed a DHCP handshake failure in concurrent mode with NAT+PAT enabled in congested environments. | None |
|
Fixed in 4.0.0#
| ID | Issue Description | GitHub / Salesforce Reference (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|
| 1559294 | Resolved an issue where consecutive HTTPS requests (GET/PUT/POST) could fail due to incomplete socket cleanup. | None |
|
| 1528819 | Resolved HTTP server stability issues under congested network conditions. | None |
|
| 1535940 | Resolved remote termination issues occurring during socket open/close operations in a loop. | None |
|
| 1498368 | Resolved a DTLS synchronization issue that could interrupt data transmission and reception. | None |
|
| 1463929 | Resloved a wrap operation issue when performing TLS transmission and HMAC operations concurrently in two application threads. | None |
|
| 1454747 | Resolved firmware upgrade stability issues with proper resource cleanup. | None |
|
| 1392151 | Resolved TLS data transfer stability issues in 352/320k mode when power save is enabled. | None |
|
Chip Enablement#
Added in 4.0.1#
None
Added in 4.0.0#
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 4.0.1#
None
Added in 4.0.0#
| Example Name | Description | Supported Software Variants (if applicable) | Supported Modes | Supported OPNs / Boards / OPN Combinations | Supported Host Interfaces |
|---|---|---|---|---|---|
|
Paho MQTT Client over LwIP TCP See README |
Demonstrates configuring a SiWx91x device as an MQTT client using the Paho MQTT library over TCP/IP with the LwIP stack. Connecting to an MQTT broker in Wi-Fi station mode to subscribe to topics and publish messages, with optional SSL/TLS encryption support. | Standard and Lite |
|
|
SPI, UART |
|
mDNS Advertising and Discovery See README |
Demonstrates how to use Multicast DNS (mDNS) to discover services and devices on the local network. Shows registration and resolution of service instances. | Standard and Lite |
|
|
SPI, UART |
Modified Examples#
Modified in 4.0.1#
| Example Name | Changes | Supported Software Variants (if applicable) | Supported Modes | Supported OPNs / Boards / OPN Combinations | Supported Host Interfaces |
|---|---|---|---|---|---|
|
TCP RX Throughput
README |
Increased the TCP RX window size from 20 to 44 (64KB) for improved throughput. Introduced updated socket configurations for enhanced TCP RX performance. Updated TCP_RX_WINDOW_SIZE_CAP and TCP_RX_WINDOW_DIV_FACTOR for optimized throughput.
|
Standard and Lite |
|
|
SPI, UART |
|
AT Commands
README |
Improved validation during socket setup. Added support for AT M4 power save commands. Enhanced BSD socket command handling for greater reliability. |
Standard and Lite |
|
|
SPI, UART |
|
LWIP MQTT Over TCP
README |
Corrected handling of IPv6 errors to ensure robust MQTT operation over IPv6. | Standard and Lite |
|
|
SPI, UART |
|
Embedded MQTT Client
README |
Changed the IS_MESSAGE_RETAINED flag default value to 0 so MQTT messages are not retained by default.
|
Standard and Lite |
|
|
SPI, UART |
|
Provisioning
README |
Added a 1-second client_idle_time timeout to the HTTP server configuration to prevent hangs caused by slow or unresponsive clients.
|
Standard and Lite |
|
|
SPI, UART |
Modified in 4.0.0#
None
Removed Examples#
Removed in 4.0.1#
None
Removed in 4.0.0#
None
Deprecated Examples#
Deprecated in 4.0.1#
None
Deprecated in 4.0.0#
None
Known Issues and Limitations#
Added in 4.0.1#
| ID | Issue or Limitation Description | GitHub / Salesforce Reference (if any) | Workaround (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|---|
| 1600748 | HTTP/HTTPS PUT operations fail when executed in a loop due to missing variable resets (http_rsp_received and callback_status) in reset_http_handles() function. | None | Reset http_rsp_received to 0 and callback_status to SL_STATUS_OK in the reset_http_handles() function after each HTTP/HTTPS PUT operation. |
|
| 1600016 | The DUT becomes unresponsive to repeated mDNS query messages. | None | None |
|
| 1607288 | When IPv6 is enabled with LwIP timer optimization, the DUT may take more than 30 seconds to join certain access points. This behavior is observed only with specific AP models. | None | None |
|
Added in 4.0.0#
| ID | Issue or Limitation Description | GitHub / Salesforce Reference (if any) | Workaround (if any) | Affected Software Variants, Hardware, Modes, Host Interfaces |
|---|---|---|---|---|
| 1427832 | Observed TLS data transfer failures in congested environments during long runs when power save is enabled. | None | None |
|
| 745282 |
Occasionally, during a TLS handshake, the device generates incorrect ECC curve parameters, causing a connection failure that results in a BBD2 error.
|
None | The error is recovered in the next attempt. |
|
| 1133422 | HTTP PUT does not support the SNI extension. | None | None |
|
| 1570754 | WebSocket connections could fail with error code -3 when connecting to certain servers. | None | None |
|
| 1571019 | mDNS discovery may fail when data transfer is active during multiple iterations. | None | None |
|
| 1571021 | mDNS start/stop with multiple services fails during multiple iterations. | None | None |
|
| 1571024 | SRV and TXT query types in mDNS discovery are currently not functioning as expected. | None | None |
|
| NA | The power-saving benefits of the hosted Network Stack LWIP may not be fully realized when IPv6 mode is enabled if the network infrastructure lacks IPv6 support. | None | None |
|
| NA | External connections to services hosted within the NAT environment are not supported. | None | None |
|
| NA | NAT/PAT is incompatible with protocols and applications that embed IP address and port number information within the payload (examples include SMTP, SNMP, and similar protocols). | None | None |
|
| NA | Network traffic translation and additional processing requirements result in increased latency and reduced throughput performance. | None | None |
|
| NA | Inbound traffic routing is not supported by the current implementation. | None | None |
|
| NA | Outbound ICMP traffic (ping requests) is restricted to a maximum payload size of 300 bytes. | None | None |
|
| N/A | TLS or DTLS connections must be initiated sequentially after the completion (success or failure) of the previous connection. | None | None |
|
| N/A | Power save with TCP/IP is not supported with the UART host interface in the non-bypass mode. | None | None |
|
| N/A | Embedded MQTT usernames are supported only up to 120 bytes. | None | None |
|
| N/A | Embedded MQTT topic lengths are supported only up to 200 bytes. | None | None |
|
| N/A | Embedded MQTT passwords are supported only up to 62 bytes. | None | None |
|
| N/A | HTTP GET URL lengths are only supported up to 2048 bytes. | None | None |
|
| N/A | More than three SSL connections are not supported. | None | None |
|
| N/A | The combined length of the mDNS service type and instance name is limited to 30 bytes maximum. | None | None |
|
| 1569000 | TCP socket send API fails with error code 33 in at_commands application on SoC with encryption enabled, preventing TCP data transmission. | None | None |
|
| 1562633 | MQTT publishing stops during BLE + Wi-Fi coexistence testing when BLE scanning is active in long run. | None | None |
|
| 1556585 | Automatic reconnection to AWS MQTT broker fails after Wi-Fi rejoin in NCP mode. If rejoin interval exceeds 10 seconds, the application hangs waiting for select_sem semaphore (timeout after 512 seconds). Manual reconnection or device reboot is required. Issue is NCP-specific and does not occur in SoC mode. | None | None |
|
| 1574418 |
Using slc generate --toolchain gcc or slc generate --with toolchain_gcc may fail with exclusivity errors due to the wiseconnect_toolchain_gcc_standard component incorrectly providing toolchain_gcc, resulting in a conflict with the Simplicity SDK 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 |
|