# Migration Guide (v2 → v5)

This guide covers breaking changes when upgrading from casper-js-sdk v2 to v5.

## Key Changes

### Package name unchanged
```bash
npm install casper-js-sdk
```

### Entry point changed

v2:
```ts
import { CasperClient, DeployUtil, CLValue } from 'casper-js-sdk';
```

v5:
```ts
import { RpcClient, HttpHandler, CLValue, Transaction } from 'casper-js-sdk';
```

### CasperClient → RpcClient

The monolithic `CasperClient` is replaced by a focused `RpcClient` with `HttpHandler` transport.

v2:
```ts
const client = new CasperClient('http://node:7777/rpc');
const balance = await client.balanceOfByPublicKey(publicKey);
```

v5:
```ts
const client = new RpcClient(new HttpHandler('http://node:7777/rpc'));
const result = await client.queryLatestBalance({
  mainPurseUnderPublicKey: publicKey.toHex(),
});
const balance = result.balance;
```

### DeployUtil → Transaction Builders

v2:
```ts
const deployParams = new DeployUtil.DeployParams(publicKey, 'casper');
const transfer = DeployUtil.ExecutableDeployItem.newTransfer(amount, target, null, id);
const payment = DeployUtil.standardPayment(100_000_000);
const deploy = DeployUtil.makeDeploy(deployParams, transfer, payment);
```

v5:
```ts
const transaction = new NativeTransferBuilder()
  .from(publicKey)
  .target(targetPublicKey)
  .amount(amount.toString())
  .id(id)
  .chainName('casper')
  .payment(100_000_000)
  .build();
```

### CLValue factories renamed

| v2 | v5 |
|---|---|
| `CLValueBuilder.u512(n)` | `CLValue.newCLUInt512(n)` |
| `CLValueBuilder.publicKey(key)` | `CLValue.newCLPublicKey(key)` |
| `CLValueBuilder.string(s)` | `CLValue.newCLString(s)` |
| `CLValueBuilder.bool(b)` | `CLValue.newCLValueBool(b)` |
| `CLValueBuilder.byteArray(bytes)` | `CLValue.newCLByteArray(bytes)` |
| `CLValueBuilder.option(inner)` | `CLValue.newCLOption(inner)` |
| `CLValueBuilder.list(items)` | `CLValue.newCLList(type)` |

### RuntimeArgs → Args

v2:
```ts
const args = RuntimeArgs.fromMap({ amount: CLValueBuilder.u512(100) });
```

v5:
```ts
const args = Args.fromMap({ amount: CLValue.newCLUInt512('100') });
```

### Key derivation

v2:
```ts
const keys = await Keys.Ed25519.new();
const publicKey = keys.publicKey;
```

v5:
```ts
const privateKey = PrivateKey.generate(KeyAlgorithm.ED25519);
const publicKey = privateKey.publicKey;
```

### Account hash

v2:
```ts
const accountHash = publicKey.toAccountHashStr();
```

v5:
```ts
const accountHash = publicKey.accountHash().toFormattedStr();
// → 'account-hash-abc123...'
```

### putDeploy → putTransaction

v2:
```ts
await client.putDeploy(deploy);
```

v5:
```ts
// For modern TransactionV1:
await rpcClient.putTransaction(transaction);

// For legacy Deploy:
await rpcClient.putDeploy(deploy);
```