First to file vs. first to invent are procedural requirements that do NOT, in any way, alter the standards for patentability. In other words, you still have to

First to file vs. first to invent are procedural requirements that do NOT, in any way, alter the standards for patentability. In other words, you still have to prove novelty, utility, nonobviousness, and sufficiency of disclosure of an invention falling within the scope of patentable subject matter. This change just brings us more in line with other members to the Paris Convention/Patent Cooperation Treaty. It's important to note that their definitions of patentable subject matter may differ from ours.