There are 2 parts to upgrading your Cloud Core. 1 is the RouterOS and the second being the Firmware. Firmware updates provide additional hardware support and resolve underlying issues with the hardware which is bundled with each RouterOS release. Its advisable to run the latest firmware offered by your RouterOS version to make sure there are no compatibility issues between the underlying hardware and the router operating system you are running.
MTCNA, MTCRE, MTCINE, MTCTCE, MTCIPv6E, MTCUME