Upgraded

Event v149 → current #14

Emitted when an account is upgraded to a new balance format.

Useful for: developersanalytics

The Big Picture

When the balance storage format changes in a runtime upgrade, existing accounts may need to be upgraded to the new format. This event signals that an account has been migrated. This is typically triggered lazily when an account is accessed after an upgrade.

Use Cases

Track account migrations during runtime upgrades
Monitor balance system upgrades
Build upgrade tracking tools

From Chain Metadata

An account was upgraded.

Triggers

Emitted by

upgrade_accounts

Preconditions

Account exists
Upgrade operation triggered

Effects

Storage Modified

Account

Postconditions

Account uses new balance storage format

Side Effects

Account data structure updated

Event Data

#	Name	Type	Description
0	who	AccountId	Who account address (hex -> SS58)

Code Examples

import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";

const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });

// Subscribe to Upgraded events
api.query.system.events((events) => {
  events
    .filter(({ event }) =>
      event.section === stringCamelCase("Balances") &&
      event.method === "Upgraded"
    )
    .forEach(({ event }) => {
      console.log("Upgraded:", event.data.toHuman());
    });
});

On-Chain Activity

Emission Frequency

●●●○○○ Active 100K–1M emissions

Regular feature-level activity

#37 most emitted event

As of block 7,429,232

Runtime Info

Pallet Index: 5
Event Index: 14
First Version: v149
Current Version: v393

Back to Balances Events