Cumulative updates are designed to simplify the maintenance of complex software environments by ensuring that every new release includes all the content of the ones that came before it.
A cumulative update is a single software package that bundles multiple previously released updates—including security patches, bug fixes, and system improvements—along with new fixes into one installation. Instead of requiring users to install dozens of individual patches chronologically, a cumulative update allows a system to reach the most current state in a single step. How Cumulative Updates Work cumulative update
Cumulative Update 12 for Exchange Server 2013 - Microsoft Support Cumulative updates are designed to simplify the maintenance