RAIL SDK Version 3.0.0 - Release Notes (Jan 22, 2026)#

Simplicity SDK Version 2025.12.0

The RAIL SDK is a complete software development suite for proprietary wireless applications. It was previously part of the Proprietary SDK. Starting with the RAIL SDK 2.18.0 release, Proprietary SDK is split into RAIL SDK and Connect SDK.

Silicon Labs RAIL (Radio Abstraction Interface Layer) is an intuitive and easily-customizable radio interface layer designed to support both proprietary and standards-based wireless protocols.

The RAIL SDK is supplied with extensive documentation and sample applications.

Release Summary#

Key Features | API Changes | Bug Fixes | Chip Enablement

Key Features#

  • RAIL 3.0.0 Library support.

  • IEEE 802.15.4 BPSK protocol support added.

API Changes#

  • New BPSK packet pack/unpack helpers and protocol enum entry; packet assistant exposes BPSK RX/TX functions.

  • Mode switch PA APIs now take only the RAIL handle (init_rail_pa_settings(sl_rail_handle_t), update_rail_pa_settings(sl_rail_handle_t)).

  • Removed the sl_rail_sdk_wmbus_phy_software() function.

Bug Fixes#

  • Light Switch payload start pointer fixed.

  • Burst duty cycle sleep-stall fixed.

Chip Enablement#

None.

Key Features#

New Features | Enhancements | Removed Features | Deprecated Features

New Features#

  • Updated RAIL SDK codebase to support the new RAIL 3.0.0. library.

  • BPSK Protocol Support**: Added IEEE 802.15.4 BPSK protocol support.

Enhancements#

  • Mode Switch PA Improvements: PA setup now initializes and updates power via the active RAIL handle, automatically detecting OFDM/FSK channels. Removed channel-specific parameters from API.

  • Protocol Enum Update: Renamed BTC protocol enum value to BPSK for clarity.

Removed Features#

Removed the WMBUS Software PHY Function, sl_rail_sdk_wmbus_phy_software(), as software-based PHY processing is no longer required.

Deprecated Features#

None.

API Changes#

New APIs | Modified APIs | Removed APIs | Deprecated APIs

New APIs#

API

Description

int16_t sl_rail_sdk_802154_packet_pack_bpsk_data_frame(uint16_t payload_size, const uint8_t *payload, uint16_t *frame_size, uint8_t *frame_buffer)

Packs IEEE 802.15.4 BPSK frame with 1-byte PHR

uint8_t *sl_rail_sdk_802154_packet_unpack_bpsk_data_frame(const sl_rail_rx_packet_info_t *packet_information, uint16_t *payload_size, uint8_t *frame_buffer)

Unpacks received IEEE 802.15.4 BPSK frame

uint16_t unpack_packet_bpsk(sl_rail_handle_t rail_handle, uint8_t *rx_destination, const sl_rail_rx_packet_info_t *packet_information, uint8_t **start_of_payload)

Packet assistant helper for BPSK RX

void prepare_packet_bpsk(sl_rail_handle_t rail_handle, uint8_t *out_data, uint16_t length)

Packet assistant helper for BPSK TX

Modified APIs#

Old API

New API

Change Description

void init_rail_pa_settings(void)

void init_rail_pa_settings(sl_rail_handle_t rail_handle)

Now requires RAIL handle parameter; initializes PA after detecting OFDM/FSK channels.

void update_rail_pa_settings(sl_rail_handle_t rail_handle, uint16_t channel)

void update_rail_pa_settings(sl_rail_handle_t rail_handle)

Removed channel parameter; applies TX power via active handle.

RAIL_SDK_Protocol_t enum: BTC = 8

RAIL_SDK_Protocol_t enum: BPSK = 8

Protocol enum value renamed from BTC to BPSK.

Removed APIs#

API

Reason

uint16_t sl_rail_sdk_wmbus_phy_software(uint8_t *buffer, uint8_t length, uint16_t buffer_length)

Software-based PHY processing for T-mode Meter-to-Other no longer required.

Deprecated APIs#

None.

Bug Fixes#

ID Issue Description GitHub / Salesforce Reference (if any) Affected Software Variants, Hardware, Modes, Host Interfaces
1563461 Light Switch sample: packet and payload handling updated to avoid drops/warnings. Changed packet received tracking from counter to boolean flag and fixed payload pointer usage. None
  • Light Switch sample application
  • All supported boards
  • SoC
  • UART, EUART interface
1525880 Burst duty cycle app could stall in sleep; fixed scheduling and added app_is_ok_to_sleep() callback to prevent sleep during packet processing and burst transmission. None
  • Burst Duty Cycle sample application
  • All supported boards
  • SoC

Chip Enablement#

None.

Application Example Changes#

New Examples | Modified Examples | Removed Examples | Deprecated Examples

New Examples#

None.

Modified Examples#

Chip Family OPNs / Boards / OPN Combinations Supported Software Variants (if applicable) Supported Modes Supported Host Interfaces
EFR32xG29
  • OPN: EFR32BG29, EFR32MG29
  • Boards: BRD4412A, BRD4413A, BRD4414A, BRD4420A
 Standard
  • SoC
  • NCP
 SPI, EUSART, UART

Application Example Changes#

New Examples | Modified Examples | Removed Examples | Deprecated Examples

New Examples#

None.

Modified Examples#

None.

Removed Examples#

None.

Deprecated Examples#

None.

Impact of Release Changes#

Impact Statements | Migration Guide

Impact Statements#

Example Name Changes Supported Software Variants if applicable Supported Modes Supported OPNs / Boards / OPN Combinations Supported Host Interfaces
All examples Using the new RAIL 3.0.0. functions. Standard
  • SoC
  • NCP
 All boards All
Proprietary radio configuration using examples. Enablement of the BSPK PHY and protocol support. Standard SoC All boards All
sl_rail_sdk_wmbus_phy_software() removed Empty function was removed for clarity. Standard SoC WMBUS applications All

Migration Guide#

Click here for the migration guide for deprecated, removed, and modified items.

Known Issues and Limitations#

ID Issue or Limitation Description GitHub / Salesforce Reference (if any) Workaround (if any) Affected Software Variants, Hardware, Modes, Host Interfaces
1268208 The power consumption of DK2600 can't be optimized if the configuration time for EM2 and if UART are both being used, as the value of SL_IOSTREAM_USART_{instance}_BAUDRATE does not take effect. The default value used instead is 115200 bps. Typical use case is RAIL - SoC Wireless M-bus Meter with DK2600 board. None Update UART baud rate to 9600 bps at Simplicity Studio Admin Console. This is necessary for EM2.
  • RAIL SDK sample applications
  • BRD2600A
  • SoC
  • UART interface
1274248 Range Test DMP instabilities in case of LTO. None Do not use LTO.
  • Range Test DMP sample applications
  • All supported boards
  • SoC
1375450 Wi-SUN HAN phys aren't supported by Standard packet assembler and Packet Assistant components. None Do not use Wi-SUN HAN phys with RAIL SDK sample applications.
  • RAIL SDK sample applications
  • All supported boards
  • SoC, NCP mode
  • UART, SPI interface
Updating the Baremetal sample applications to RTOS causes build errors. None

Follow the Platforms guide sl_main Baremetal to RTOS Application Transition.
  • RAIL SDK Baremetal sample applications
  • All supported boards
  • SoC, NCP mode
  • UART, SPI interface

Using This Release#

What's in the Release? | Compatible Software | Installation and Use | Help and Feedback

What's in the Release?#

RAIL SDK showcasing the usage of the RAIL library.

Compatible Software#

None.

Installation and Use#

To upgrade your existing software with this release, see instructions here.

To run your first demo, see our Getting Started Guides.

To kick start your development, see our Developer's Guide.

For information about Secure Vault Integration, see Secure Vault.

To review Security and Software Advisory notifications and manage your notification preferences:

  1. Go to https://community.silabs.com/.

  2. Log in with your account credentials.

  3. Click your profile icon in the upper-right corner of the page.

  4. Select Notifications from the dropdown menu.

  5. In the Notifications section, go to the My Product Notifications tab to review historical Security and Software Advisory notifications

  6. To manage your preferences, use the Manage Notifications tab to customize which product updates and advisories you receive.

To learn more about the software in this release, dive into our online documentation.

Help and Feedback#

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SDK Release and Maintenance Policy#

See our SDK Release and Maintenance Policy.