Looking at the revision history is the best way to learn about changes to the data. This is true regardless of whether you are using the API or the UI to submit data requests. In the rare circumstance of a major error in the data, we will contact users who included the affected variable by email to suggest they resubmit any data requests.
I want to include a brief aside on the POVERTY variable in particular. We recently uncovered an issue with one of the component variables in POVERTY. I would advise you to wait until we have released a corrected version to work with this variable (or use it only to test your code and submit an updated request once we have released a fix for this variable).