You will find lists of keys online (e.g., ULTRA-DMG-1234-ABCD ). 99% of these are either already blacklisted by the developer or are simply random strings. If the key does work, the software will (sooner or later) "phone home" to the developer’s server, locking you out and potentially flagging your IP address.
Supports everything from older versions like OS X El Capitan to modern releases. How to Use an UltraDMG License Key
For individuals or small businesses operating on a tight budget, the temptation to use a pirated Ultra DMG license key is understandable. However, the risks associated with downloading cracked software or key generators (keygens) often outweigh the cost of the software itself.