If you need help with the next steps of your deployment, please let me know:
If you cannot get access to the official ISO through a Cisco contract, consider these legitimate alternatives:
Once the download is complete, verify the integrity of the ISO image by checking its MD5 checksum. This ensures that the file has not been corrupted during the download process.
Do you already have access to an official with download permissions? Which VMware ESXi version are you hosting this on?
CUCM 12.5 requires strict adherence to Cisco’s Open Virtual Appliance (OVA) templates. Installing CUCM on a custom-configured VM without the correct specifications is unsupported and will cause performance degradation. Step 1: Download the Correct OVA Template
Navigate to Cisco Unified OS Administration -> System -> Smart Licensing within CUCM to register the cluster and assign your purchased user licenses.
A significant number of lab users, home-lab enthusiasts, and IT professionals learning for certification (like CCNP Collaboration) do not have access to a commercial license for a lab environment. For those in a non-production setting, the community has developed methods to create a bootable ISO from the standard, downloadable, non-bootable update file.
Once the OVA is deployed and the bootable ISO is uploaded to your ESXi datastore, follow these steps to execute the installation:
A bootable ISO image is a self-contained file that contains the entire operating system and software installation. It allows you to create a bootable USB drive or DVD, which can be used to install or upgrade your CUCM system. Having a bootable ISO image of CUCM 12.5 ensures that you can quickly and easily install or recover your system in case of a failure or disaster.
Widely available on the Cisco Software Download site for any user with a valid service contract. How to Legally Download CUCM 12.5 Software
If you only have access to the non-bootable upgrade file, it is possible to make it bootable for lab environments (like EVE-NG or VMware) using third-party tools: