https://bugs.chromium.org/p/chromium/issues/detail?id=653691 (https://bugs.chromium.org/p/chromium/issues/detail?id=653691#c5)

Chrome 57 won't accept certificate chains that contain SHA-1 within them, so we need to be sure that Fiddler/FiddlerCore default to SHA-256 everywhere. We also might consider whether we should detect that the user has old Fiddler-generated SHA-1 certificates cached and if so, clean those up and generate a fresh cert using SHA-256.