The built-in Syncthing library was updated to 2.1.1. So be sure to read about the major changes in 2.1 on https://github.com/syncthing/syncthing/releases/tag/v2.1.1 if you are using the built-in Syncthing library.
This release contains no changes in Syncthing Tray itself. It only updates the built-in Syncting library and changes build flags for Windows ARM to address #443.
Full Changelog: v2.1.1...v2.1.2