SDK 2.7.0 introduces a new OTA update mechanism (called ApplicationLoader). Along with that, the surroundings of bootloader have been changed.

The main changes are as follows.

• The Bluetooth stack has been changed to be provided as a library instead of as a binary.
• Before: /protocol/bluetooth_2.6/lib//EABI/binstack.o
• After change: /protocol/bluetooth_2.7/lib///libbluetooth.a
• When using OTA update, you need to include the ApplicationLoader binary in your project. Application Loader is provided below. It is included by default in the sample code for SOC.
• gecko_sdk_suite/v2.1/protocol/bluetooth_2.7/lib///binapploader.o
• ApplicationLoader assumes the use of the latest gecko bootloader and will not work on the legacy legacy bootloader. Therefore, if you are using the conventional bootloader, you will need to replace it with the latest geckobootloader.
• Legacy bootloader was included in the sample code of the old SDK by default, but bootloader is not included in the sample code of SDK2.7.0. You need to generate and download the gecko bootloader from New Project, or download the demo app (not the sample code) once.
• Along with providing the ApplicationLoader and Bluetooth stack libraries, the layout of the library and memory has changed.
• Removed aat.h from main.c as it is no longer needed.
• Removed boards.h and moved contents to ble-configuration.h.

More information can be found on the SiliconLabscommunity site here.