Here is a second beta test for Teensyduino 1.60.
Arduino 2.3.x, all systems:
https://www.pjrc.com/teensy/td_160-beta2/package_teensy_0.60.2_index.json
Quit Teensy Loader, if running
Use Boards Manager to uninstall Teensy, if previously installed
Use File > Preferences (Arduino IDE > Settings...