The Federal Circuit recently reversed a district court decision that found a patent that did not describe after-arising technology failed to satisfy the written description requirement. In so doing, the Federal Circuit explained that written description and enablement are evaluated based on the subject matter that is claimed, not the products that practice those claims. As a result, the patentee was not required to describe unclaimed, later-discovered features of the accused products despite the broad language in the claims that undisputedly covered the products.