New default BLE Link Layer
With the merge of PR #15781, the new "split" Link Layer is now the default for BLE-enabled applications. Extensive development and testing effort has gone into this feature, but there might be regressions that have slipped through the testing procedures. Please open issues on GitHub if you come across any issues when testing your applications with it.
You can revert back to using the previous Link Layer by enabling the CONFIG_BT_LL_SW_LEGACY Kconfig option.
Thank you to everybody involved in this feature for making it happen. New features that were not possible to implement with the old architecture will now slowly start coming to the new Link Layer.