I've used grid with IE11. You need to add some extra prefixing noise to your css. The way you identify grid elements is different and it sucks to duplicate the layout information.
But it most definitely works.
But it most definitely works.
Which means, if you need to support IE10, you need a whole parallel set of styles. There's no graceful degradation when it comes to overall site layout, unless you're willing to serve the single-column mobile version to older browsers.
Who in the world has that as a significant user base?