On January 7, 2019, the US Patent and Trademark Office issued revised guidance on whether an invention is eligible for patenting. (For example, can you patent a method of hedging risk?)
Patent law has always been, and remains, unpredictable on the eligible-for-patenting point. But the Supreme Court’s decision in Alice Corp. v. CLS Bank (2014) reset much of the case law that had built up, and it therefore allowed district court judges wide latitude to invalidate “bad patents” on the basis that the underlying ideas simply weren’t eligible. The sudden spike in invalidations increased the sense that the law was unpredictable.
Hence, there is much guidance and revised guidance on whether certain ideas are patentable. But I hate reading this kind of guidance; it’s boring. So I drew a picture.

The main revision appears to be the following:
Examiners should note, however, that revised Step 2A specifically excludes consideration of whether the additional elements represent well-understood, routine, conventional activity. Instead, analysis of well-understood, routine, conventional activity is done in Step 2B. Accordingly, in revised Step 2A examiners should ensure that they give weight to all additional elements, whether or not they are conventional, when evaluating whether a judicial exception has been integrated into a practical application.
And… you’re welcome.