Transazioni Versionate

Versioned Transactions are the new transaction format that allow for additional functionality in the Solana runtime, including Address Lookup Tables.

While changes to onchain programs are NOT required to support the new functionality of versioned transactions (or for backwards compatibility), developers WILL need update their client side code to prevent errors due to different transaction versions.

Current Transaction Versions #

The Solana runtime supports two transaction versions:

• legacy - older transaction format with no additional benefit
• 0 - added support for Address Lookup Tables

Max supported transaction version #

All RPC requests that return a transaction should specify the highest version of transactions they will support in their application using the maxSupportedTransactionVersion option, including getBlock and getTransaction.

An RPC request will fail if a Versioned Transaction is returned that is higher than the set maxSupportedTransactionVersion. (i.e. if a version 0 transaction is returned when legacy is selected)

How to set max supported version #

You can set the maxSupportedTransactionVersion using both the @solana/web3.js library and JSON formatted requests directly to an RPC endpoint.

Using web3.js #

Using the @solana/web3.js library, you can retrieve the most recent block or get a specific transaction:

// connect to the `devnet` cluster and get the current `slot`
const connection = new web3.Connection(web3.clusterApiUrl("devnet"));
const slot = await connection.getSlot();
 
// get the latest block (allowing for v0 transactions)
const block = await connection.getBlock(slot, {
  maxSupportedTransactionVersion: 0,
});
 
// get a specific transaction (allowing for v0 transactions)
const getTx = await connection.getTransaction(
  "3jpoANiFeVGisWRY5UP648xRXs3iQasCHABPWRWnoEjeA93nc79WrnGgpgazjq4K9m8g2NJoyKoWBV1Kx5VmtwHQ",
  {
    maxSupportedTransactionVersion: 0,
  },
);

JSON requests to the RPC #

Using a standard JSON formatted POST request, you can set the maxSupportedTransactionVersion when retrieving a specific block:

curl https://api.devnet.solana.com -X POST -H "Content-Type: application/json" -d \
'{"jsonrpc": "2.0", "id":1, "method": "getBlock", "params": [430, {
  "encoding":"json",
  "maxSupportedTransactionVersion":0,
  "transactionDetails":"full",
  "rewards":false
}]}'

How to create a Versioned Transaction #

Versioned transactions can be created similar to the older method of creating transactions. There are differences in using certain libraries that should be noted.

Below is an example of how to create a Versioned Transaction, using the @solana/web3.js library, to send perform a SOL transfer between two accounts.

Notes: #

• payer is a valid Keypair wallet, funded with SOL
• toAccount a valid Keypair

Firstly, import the web3.js library and create a connection to your desired cluster.

We then define the recent blockhash and minRent we will need for our transaction and the account:

const web3 = require("@solana/web3.js");
 
// connect to the cluster and get the minimum rent for rent exempt status
const connection = new web3.Connection(web3.clusterApiUrl("devnet"));
let minRent = await connection.getMinimumBalanceForRentExemption(0);
let blockhash = await connection
  .getLatestBlockhash()
  .then(res => res.blockhash);

Create an array of all the instructions you desire to send in your transaction. In this example below, we are creating a simple SOL transfer instruction:

// create an array with your desired `instructions`
const instructions = [
  web3.SystemProgram.transfer({
    fromPubkey: payer.publicKey,
    toPubkey: toAccount.publicKey,
    lamports: minRent,
  }),
];

Next, construct a MessageV0 formatted transaction message with your desired instructions:

// create v0 compatible message
const messageV0 = new web3.TransactionMessage({
  payerKey: payer.publicKey,
  recentBlockhash: blockhash,
  instructions,
}).compileToV0Message();

Then, create a new VersionedTransaction, passing in our v0 compatible message:

const transaction = new web3.VersionedTransaction(messageV0);
 
// sign your transaction with the required `Signers`
transaction.sign([payer]);

You can sign the transaction by either:

• passing an array of signatures into the VersionedTransaction method, or
• call the transaction.sign() method, passing an array of the required Signers

After your VersionedTransaction has been signed by all required accounts, you can send it to the cluster and await the response:

// send our v0 transaction to the cluster
const txId = await connection.sendTransaction(transaction);
console.log(`https://explorer.solana.com/tx/${txId}?cluster=devnet`);

More Resources #

• using Versioned Transactions for Address Lookup Tables
• view an example of a v0 transaction on Solana Explorer
• read the accepted proposal for Versioned Transaction and Address Lookup Tables