Fedora’s new Offline System Update feature will change the current system to something that is more Windows- and OS X-like: while many updates can still be made on the fly, certain package updates will require the system to be restarted so the patches can be applied in a special mode, according to the Fedora wiki page on the feature.
“By ‘offline’ OS updates we mean package installations and updates that are run with the system booted into a special system update mode, in order to avoid problems related to conflicts of libraries and services that are currently running with those on disk,” the wiki states. “Updates will be downloaded in the background, and the user will be informed about available updates only once they are actually ready to be installed.”