This release adds a tiny new feature: before you could have configured durations and end time to pull information from attribute, fixed, and entity, but now there's a fourth option: state!
This is useful if you are using this card for alarms! Let's say your alarm's state is set to the time it will go off. You can use end_time: { state: true } together with guess_mode: true to get the card working!
Yes, you could have done this before with the entity attribute, but this way will make your configuration nicer!