This page: https://github.com/jasper-software/xv contains updated versions of xv ("[m]any changes/improvements have been made on top of the original code"). The repository apparently exists with the approval of the original author - "The creator of this GitHub repository (Michael Adams) would like to thank John Bradley for giving his blessing for a public Git repository for the XV software." The new maintainers released version 4.2.0 on 2023-07-17.