For legacy hardware, consider migrating to Proxmox VE or XCP-ng, which are modern, free, and open-source alternatives.

These are not "cracked" keys. They are legitimate, time-limited licenses obtained directly through a VMware-sanctioned program, making them completely legal and safe to use. The licenses are typically for the latest versions (vSphere 8), but the member's portal grants access to download installers for older versions, including 5.5. It's important to note that ESXi 5.x licenses and later versions are not forward or backward compatible; a newer license will not activate an older version. However, a VMUG Advantage subscription legally allows the use of older versions for learning purposes, providing a much safer environment than GitHub keys.

Newer server hardware may not support the older drivers found in version 5.5. 🛡️ Better Alternatives

What (brand and model) are you currently running?

Secret storage & encryption

Access control

The following example demonstrates how to manage ESXi 5.5 license keys using a GitHub repository: