# Upgrading core modules

{% hint style="warning" %}
This page mentions many unimplemented features.
{% endhint %}

If you want to add or remove variables managed by Policy Contract or change existing specifications, you need to upgrade the core modules on Dev Protocol.

## Smart contracts that upgraders should implement

In order to upgrade the core modules, the developer needs to develop the following smart contracts.

### 1. Patch contracts

Prepare smart contracts with patches applied to existing core modules or smart contracts that implement newly added modules.

### 2. Writer contract

Prepare a smart contract to apply the patch.

A writer contract needs to be created as self-destructible contracts, as they are one-time contracts used for patching purposes.

The following interfaces are required for a writer contract.

#### write

This function is called after the authority is temporarily transferred from the Upgrader Contract(unimplemented), and it is necessary to apply the patch with one call.

```
function write() external;
```

#### close

Self-destruct. It would help if you verified that a caller is an Upgrader Contract(unimplemented).

```
function close() external;
```

## Upgrader Contract

A contract is responsible for managing the authority to upgrade the Dev Protocol core modules and enforcing core module upgrades passed by on-chain governance.

Upgrader Contract allows upgrade itself with a patch contract.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://dev-protocol.gitbook.io/dev-protocol/protocol/governance/upgrading-core-modules.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.