A hotpatch is an update applied to running software without a full upgrade and with little or no downtime. Instead of installing a complete new version, a hotpatch changes only the specific components needed to fix an issue, often a security problem. Some vendors provide them for enterprise products so that urgent fixes can be applied quickly.
The main benefit is speed and low disruption. Administrators can close a vulnerability without scheduling a long maintenance window, and the system stays close to the version it was already running.
Hotpatches have limits. They usually cover only certain fixes, may still need services to restart or a brief interruption, and are not a substitute for regular upgrades. Over time, systems that rely only on hotpatches can drift away from the supported version, and a later full upgrade may still be required. Applying a hotpatch also does not by itself prove that a system is secure.
When a vendor offers one, read its notes for which issues it fixes and what it affects, back up first, apply it as instructed and confirm the version and build afterwards. Plan to move to the next full release so that the system stays supported.