Version 0.171u fixes a bug in the default config file embedded in the firmware. If you have a twiddler.cfg file on your Twiddler (custom or factory) this is a non-essential bug fix. Upgrading is only recommended if you use the factory default chord map (N+S M000).
Firmware located here: https://twiddler.tekgear.com/doc/doku.php?id=twiddler_firmware&#twiddler_firmware