Last week, the Federal Circuit Court of Appeals imposed important limitations on the post-Alice doctrine of software patent invalidity—patent owners everywhere could be heard sighing in relief. In Enfish, LLC v. Microsoft Corp. (No. 2015-1244, available at http://www.cafc.uscourts.gov/sites/default/files/opinions-orders/15-1244.Opinion.5-10-2016.1.PDF), the Federal Circuit reversed a Central District of California judge’s finding that software claims directed to an “innovative logical model for a computer database” were invalid under 35 U.S.C. § 101 as directed to an abstract idea. Under Alice Corp. Pty Ltd. v. CLS Bank Int’l, 134 S. Ct. 2347, 2355 (2014), the familiar two-step process for determining § 101 validity is: first determining whether the claim at issue is directed to a patent-ineligible concept, i.e., an abstract idea; and if it is, second, considering whether the claim’s additional elements transform the nature of the claim into a patent-eligible application. While most post-Alice software patent cases have turned on the second step, Enfish makes the first step more meaningful, imposing a greater burden on parties attempting to invalidate a software claim.