How suspicious should we be about the 'new' Harper Lee novel?

Citation

Squires C (2015) How suspicious should we be about the 'new' Harper Lee novel?. The Conversation. 06.02.2015. https://theconversation.com/how-suspicious-should-we-be-about-the-new-harper-lee-novel-37182

Abstract
First paragraph: A sequel to Harper Lee's classic 1960 novel To Kill a Mockingbird has been "found", and will be published in July, her US publisher HarperCollins has announced. The sequel - Go Set a Watchman - was written before To Kill a Mockingbird, but Lee's editor persuaded her to take her grown-up character Scout back in time, and the multi-million selling novel was born, and the "sequel" discarded. Until now.