A Patch is a software component that is installed onto a device that modifies files or device settings. Patches are typically done to fix an issue with a device or software solution. Often times, patches are released by vendors to address a critical security bug, or vulnerability.
Purchasing Commercial-Off-The-Shelf (COTS) software helps ensure a steady development cycle that includes patches for the software running your business. Just be aware that all software can go end-of-life and end-of-support which means the software developer will no longer issue patches to fix problems. In these situations you need to upgrade to a more current version of hardware or software to continue to receive patches for your IT infrastructure.