> For the complete documentation index, see [llms.txt](https://docs.fbtc.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fbtc.com/security/risk-management/upgradability.md).

# Upgradability

The contract upgrade mechanism is a fundamental feature of the FBTC project, allowing the system to evolve and improve over time without disrupting existing operations. By leveraging proxy contracts and a well-defined upgrade process, FBTC ensures that contract upgrades can be implemented smoothly and securely.

## Upgradability

FBTC achieves on-chain logic through a combination of proxy contracts and implementation contracts:

* **Proxy Contract**: This is the contract with which users and other system components interact. All data is stored in the proxy contract.
* **Implementation Contract**: This contract contains the core logic but does not store any data.

FBTC uses the OpenZeppelin `TransparentUpgradeableProxy` contract to enable contract upgradability. During an upgrade, the proxy contract points to the newly deployed implementation contract without changing the proxy contract's address.

For more details, please refer to:

* [Upgrades via the Proxy Pattern](https://docs.openzeppelin.com/upgrades-plugins/1.x/proxies#upgrading-via-the-proxy-pattern)
* [Transparent Proxies](https://docs.openzeppelin.com/upgrades-plugins/1.x/proxies#transparent-proxies-and-function-clashes)


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