Re:Wait a second... (Score 1)

It's even possible to update/upgrade on-the-fly while the program is running. This is not a problem for client application as it's no issue to shutdown Open Office or Firefox to update, but a server program busy serving hundreds of clients that depend up on it.

With Shared Libraries in C/C++ and classes, etc in other languages one can create a architecture design of empty skeleton to hold all code as individual loadable modules that can be loaded/unloaded anytime. So you can load v2 of a module, tell the app switch over to use the new module and then unload the old v1.