Not really. It's technically possible with Ksplice, but almost no distro actually supports it.
Beyond the kernel, you have various libs and binaries that will be replaced during upgrades. All can usually/mostly be restarted without a reboot, but just upgrading packages alone won't guarantee all running processes have been updated.
Beyond the kernel, you have various libs and binaries that will be replaced during upgrades. All can usually/mostly be restarted without a reboot, but just upgrading packages alone won't guarantee all running processes have been updated.