I've finally diagnosed and fixed the build problem with the TEI Jenkins server. It was caused by a change in the way Jenkins handles the archiving of artifacts; it stopped making symlinks on the file system to point to the latest successful build products, and instead uses a text file that has to be parsed. We use those symlinks to build other jobs using the products of previous jobs, so I've added a build step that parses the text file and recreates the symlink, and that seems to be working. 120 minutes altogether, over a couple of weeks.