As much as a footgun HTTP Public Key Pinning was, HPKP would have solved a lot of issues/caveats mentioned in the article. That said, I'm going to add this for

As much as a footgun HTTP Public Key Pinning was, HPKP would have solved a lot of issues/caveats mentioned in the article. That said, I'm going to add this for my domains (all of which use Letsencrypt anyway).