A cumulative update is a cumulative set of files that includes all hotfixes and regulatory features that have been released for Microsoft Dynamics 365 Business Central.
The latest cumulative update listed in this article includes hotfixes and regulatory features released for Microsoft Dynamics 365 Business Central, including hotfixes and regulatory features released in previous cumulative updates.
You should always install the latest cumulative update.
CU03 for MSDYN365BC On-premise is available