# Native - from v1.11

## Contract Migration on Secret Network

Contracts on Secret Network can be initialized as **migratable**, which allows the contract administrator to upload a new version of the contract and then send a `migrate` message to move to the new code, which "migrates" storage from a previous contract to the new contract.

There are two key components to a migratable contract:

* A designated `admin` whose address will be allowed to perform migrations.
* The availability of a `MigrateMsg` transaction.

### Contract Admin

On [`instantiation`](https://github.com/scrtlabs/secret.js/blob/5b98a6d7e527228b16706ff32b85d303be7714b2/src/tx/compute.ts#L48C24-L48C24), the contract creator can specify an `admin` address, which can be the contract creator's wallet address, an external account, or a governance contract, etc. Whatever the address is, this `admin` gains the ability to migrate the contract to a new `codeId` and `codeHash`, and can also update or clear the `admin` address. When the `admin` invokes the `MigrateMsg` message, the `migrate()` function is called on the new contract, where the new contract can optionally perform state migrations from an old contract.

{% hint style="info" %}
Once the `migrate()` function is invoked, the contract address now points to the new code, and anybody contacting that address will reach the new code. The old code becomes unreachable.
{% endhint %}

### MigrateMsg

Performing a contract migration is a three step process:

1. Write a newer version of the contract you wish to update
2. Upload the new smart contract, but don’t instantiate it
3. Use a dedicated [MigrateMsg](https://github.com/scrtlabs/SecretNetwork/blob/139a0eb18/cosmwasm/contracts/v1/compute-tests/migration/contract-v2/src/contract.rs#L37-L43) transaction to point the new contract to the code you wish to migrate

When migrating, the new contract must have a `migrate` function as an `entry_point.`

{% code overflow="wrap" %}

```rust
#[entry_point]
pub fn migrate(_deps: DepsMut, _env: Env, msg: MigrateMsg) -> StdResult<Response> {
    match msg {
        MigrateMsg::Migrate {} => Ok(Response::default()),
        MigrateMsg::StdError {} => Err(StdError::generic_err("this is an std error")),
    }
}
```

{% endcode %}

The `migrate` function provides the ability to make any desired changes to the contract's state, similar to a database migration.

If the `migrate` function returns an error, the transaction will abort and no state changes will occur.

### Execute Migration with Secret.js

{% code overflow="wrap" %}

```javascript
import { SecretNetworkClient, Wallet } from "secretjs";
import dotenv from "dotenv";
dotenv.config();

const wallet = new Wallet(process.env.MNEMONIC);

const secretjs = new SecretNetworkClient({
  chainId: "pulsar-3",
  url: "https://api.pulsar.scrttestnet.com",
  wallet: wallet,
  walletAddress: wallet.address,
});

const codeId = 1; // codeId for new contract
const contractCodeHash = ""; // codeHash for new contract
const contractAddress = ""; // contract address, which doesn't change upon migration

let main = async () => {
  const migrateMsg = {
    remove_users: { a, b }, // this is an example. migrateMsg can be left empty if contract storage is unchanged during migration
  };

  const tx = await secretjs.tx.compute.migrateContract(
    {
      code_id: codeId,
      contract_address: contractAddress,
      sender: wallet.address,
      code_hash: contractCodeHash,
      msg: migrateMsg,
    },
    {
      gasLimit: 400_000,
    }
  );

  console.log(tx.rawLog);
};

main();
```

{% endcode %}

### Query contract migratability

Secret contracts instantiated prior to the v1.11 network upgrade can be migrated via a SCRT governance signaling proposal. If approved for migration, the contracts' code hashes will be matched to a chosen admin key and added to a list which is hardcoded inside the enclave for reference.

{% hint style="info" %}
[Further reading on hardcoded admin list](https://forum.scrt.network/t/an-update-on-the-contract-upgrade-feature/7012/2)
{% endhint %}

In order for a Secret contract instantiated after the v1.11 network upgrade to be migrated, **the contract must be instantiated with an admin**. To query whether or not a Secret contract was instantiated with an `admin`, use the `contractInfo` method:

```javascript
let queryContractInfo = async () => {
  let query = await secretjs.query.compute.contractInfo({
    contract_address: contractAddress,
    code_hash: contractCodeHash,
  });

  console.log(query);
};
queryContractInfo();
```

The query will return the admin address, if there is one:

{% code overflow="wrap" %}

```javascript
{
  contract_address: 'secret15l8cqadh5pruweuxvr5ku830hamqny8ey2q2vf',
  contract_info: {
    code_id: '1303',
    creator: 'secret1j7n3xx4sfgjea4unghd78qvnvxdz49cxmrkqlj',
    label: 'migrate example',
    created: { block_height: '1088301', tx_index: '0' },
    ibc_port_id: '',
    admin: 'secret1j7n3xx4sfgjea4unghd78qvnvxdz49cxmrkqlj',
    admin_proof: 'TSxuJZZG0/eYGggmXNXw79So9jET3zLIy2An9bB5dA0='
  }
}
```

{% endcode %}

**To query if a Secret contract was migrated successfully**, use the [`contractHistory`](https://github.com/scrtlabs/secret.js/blob/5b98a6d7e527228b16706ff32b85d303be7714b2/src/query/compute.ts#L245C3-L245C24) method:

```javascript
let queryContractHistory = async () => {
  let query = await secretjs.query.compute.contractHistory({
    contract_address: contractAddress,
    code_hash: contractCodeHash,
  });

  console.log(query);
};
queryContractHistory();
```

The method is designed to retrieve the history of a contract, specifically its code changes over time. The method returns an object containing an array of `ContractCodeHistoryEntry` items.