v1.1 makes some small modifications to internal behavior and heartbeat length. The most important fix as part of this release is addressed at an issue whereby the button would light up but nothing would print if the device was left for a significant length of time. I believe this is due to the auto-low-power mode on the printer, which is not well documented; v1.1 adds a sleep-wake command to printMessage() to ensure the printer is awake and listening.
Full Changelog: v1.0...v1.1