Very interesting to see how on-line upgrades are becoming more mainstream; 10 years ago they were more of a curiosity, relevant to only specific industries. My research group has been working on the technical problem of dynamically updating running software for quite a while. See our research page for details: http://www.cs.umd.edu/projects/PL/dsu/ If you want just one paper to read, check out http://www.cs.umd.edu/~mwh/papers/ginseng.pdf Ksplice is doing limited dynamic updates for the Linux kernel: http://www.ksplice.com/ We're developing a new implementation that should be less invasive and more backward compatible for application programs. It's a fun area to work in!