The $UP contract is not upgradable, meaning that any changes or improvements that might be desired cannot be implemented using the current version of the contract. This is because the contract is written in a static language and any changes would require rewriting the code from scratch. This means that any new features or improvements that might be desired would need to be implemented in a new contract, rather than modifying the existing one. This can be a lengthy and costly process, and may not be feasible for many projects.