chain_subscribeRuntimeVersion - Bittensor RPC Method

Subscribes to runtime version changes over a WebSocket connection. Each time the Bittensor runtime is upgraded, this subscription emits a notification containing the new runtime version details. This allows applications to detect upgrades in real time and update their type registries, metadata, and decoders accordingly.

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": "chain_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.chain.subscribeRuntimeVersion((version) => {
  console.log(`Runtime upgrade detected: specVersion=${version.specVersion}`);
  console.log(`Transaction version: ${version.transactionVersion}`);
});

// Later: unsub();

Use Cases

• Runtime upgrade detection -- React to runtime upgrades by refreshing metadata and type registries so your application can decode new extrinsic and storage formats.
• Indexer maintenance -- Pause or restart indexing pipelines when a runtime upgrade changes storage layouts or extrinsic formats.
• Dashboard alerts -- Display notifications to operators when the Bittensor runtime version changes.

Notes

• The first notification is emitted immediately with the current runtime version.
• Cancel the subscription with chain_unsubscribeRuntimeVersion when no longer needed.
• The transactionVersion field is critical: if it changes, previously constructed unsigned extrinsics may no longer be valid.

Related Methods

• chain_unsubscribeRuntimeVersion -- Cancel this subscription
• state_subscribeRuntimeVersion -- Equivalent subscription via the state namespace
• chain_getRuntimeVersion -- One-shot query for current runtime version
• state_getMetadata -- Get the full runtime metadata after detecting an upgrade