We do this in q/kdb+ systems often for patches. An important thing about these languages is that this kind of workflow is part of the core for solving problems. So when you are building a system one of the aspects of its design will always allow for this update method. Then when you push a patch you both know the impact of the change (because you've tested the exact same steps in a dev/QA/UAT/Beta environment) and the work required to do it safely.

Major releases do go through a full shutdown and release cycle though.