NFSv4, or Network File System version 4, is a protocol that allows users to access files over a network as if they were on their local computer. It improves upon earlier versions by providing better security features, such as support for Kerberos authentication, and allows for more efficient data transfer. One of the key features of NFSv4 is its ability to handle file locking and management in a more streamlined way. This version also supports stateful operations, meaning it can maintain information about open files and sessions, which enhances performance and reliability in file sharing across different systems.