The Smart Stick app is for use only with Kinsa’s Smart Stick thermometer that plugs into the headphone jack of your phone, and supports temperature tracking. Temperature data integrates seamlessly with HealthKit and the Health app.
If you have a wireless Kinsa thermometer including QuickCare or Smart Ear, use the all new Kinsa app instead.

From version Kinsa Smart Stick 10.1.0:

We've extended our new Care Recommendation feature to help you manage cough symptoms! The Care Recommendation is personalized to your situation, helping you understand whether your illness is serious and what to do next, based on your age and symptoms.
Also we have fixed a few bugs.

We hope your family doesn't get sick, but if they do, we'll be there to help!

All versions
March 19, 2020
January 14, 2020
December 5, 2019
November 19, 2019
August 29, 2019
March 20, 2019
March 5, 2019
February 19, 2019