[These lines](https://github.com/getsentry/raven-js/blob/master/src/raven.js#L816-L817) will cause IE8 to fail. Interestingly, Raven bootstrapped and was able to report on the error: [](https://gyazo.com/78b4afa26b60c348d62d536bd56294fa) Raven does support IE8, right? I can open a PR to fix this if so.