The answer to your question would be that the revision that corrects the punctuation errors in the sentence is the following one: Remove the comma after "apples" and put a comma after "upstate."
The first comma should be removed (the one after apples) because it provides information that is considered essential to the meaning of the sentence, it states the time when they picked the apples. Then, there should be a comma after "upstate" because the information that follows (a relative clause further specifying the date) is non essential. As such, it should be separated from the rest of the sentence.