What is the best practice to determine what the device is currently doing and/or cancel the current operation?
Here’s the scenario: User starts a checkout but closes the app (or loses connectivity etc). User immediately reopens app and attempts to do a new checkout before the prior checkout times out.
The app can start a new payment request, but it will just be pending until the previous checkout times out.
What SDK is this with? Is it Reader SDK or is it Point of Sale API? 
Hi Bryan,
It’s the Terminal Api (https://developer.squareup.com/docs/terminal-api/overview).
The approach we selected was to query all checkouts for the last x minutes and cancel anything that’s IN_PROGRESS or PENDING for the specified device and that approach seems to work.
Great! Glad to hear you found an approach that fits the business need.