state_subscribeRuntimeVersion - JSON-RPC M...

Subscribes to runtime version updates over a WebSocket connection. Use it to detect Bittensor runtime upgrades so your indexers, signers, and type registries can refresh before decoding new blocks or extrinsics.

The initial JSON-RPC response returns a subscription ID. Runtime version objects are delivered afterward as WebSocket notifications on that subscription.

Code Examples

This method requires a WebSocket connection and is not available over HTTP.

WebSocket (wscat)

wscat -c wss://api-bittensor-mainnet.n.dwellir.com/YOUR_API_KEY \
  -x '{
    "jsonrpc": "2.0",
    "method": "state_subscribeRuntimeVersion",
    "params": [],
    "id": 1
  }'

JavaScript

import { ApiPromise, WsProvider } from '@polkadot/api';

const api = await ApiPromise.create({
  provider: new WsProvider('wss://api-bittensor-mainnet.n.dwellir.com/YOUR_API_KEY')
});

const unsub = await api.rpc.state.subscribeRuntimeVersion((version) => {
  console.log(`Runtime upgrade detected: specVersion=${version.specVersion}`);
  console.log(`Transaction version: ${version.transactionVersion}`);
});

// Later: unsub();

Use Cases

• Metadata refresh -- Detect runtime upgrades and reload metadata before decoding new blocks or extrinsics.
• Signer safety -- Watch transactionVersion changes that can invalidate previously prepared unsigned transactions.
• Operational alerting -- Notify operators or dashboards when Bittensor upgrades on-chain logic.

Notes

• The first notification typically arrives immediately with the current runtime version.
• Cancel the subscription with state_unsubscribeRuntimeVersion when you no longer need updates.
• This subscription is WebSocket-only.

Related Methods

• state_unsubscribeRuntimeVersion -- Cancel this subscription
• chain_subscribeRuntimeVersion -- Equivalent runtime-version subscription via the chain namespace
• chain_getRuntimeVersion -- One-shot runtime version query