> For the complete documentation index, see [llms.txt](https://legacy-docs.aragon.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://legacy-docs.aragon.org/developers/tools/the-basics/upgradeability.md).

# Upgradeability

{% hint style="success" %}
Make your app <mark style="color:purple;">**upgradeable**</mark> to fix bugs and push enhancements.
{% endhint %}

## How does it work?

The ACL and Forwarders allow you to create apps that are interoperable and generic so you don't have to reimplement any governance or authentication logic whatsoever. This is thanks to Proxies.

A **Proxy** is a very simple smart contract that consists of decoupling the instance of a particular smart contract with the location of its actual business logic.

All a Proxy does is **delegate calls to another contract that contains its actual logic**.

This allows for **upgradeability** since **you can always interact with the same Ethereum address for the smart contract** but its logic can be upgraded over time.

Proxies help enable the decoupling of authentication and logic since you do not need to authenticate any particular version of the smart contract but rather a reference to it that never changes.

We created [EIP897](https://github.com/ethereum/EIPs/pull/897), which has been merged, in order to standardize how Proxy interfaces work across all the ecosystem.

The [aragonOS Kernel](/developers/tools/the-basics/the-aragon-stack.md#the-kernel) takes care of maintaining the mapping between the Proxy address of an app and the address where its actual logic lives.

Then, upgrading an app is as easy as:

```solidity
    kernel.setApp(kernel.APP_BASES_NAMESPACE(), appId, newAppCodeAddr)
```


---

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