Upgrading Your Runtime

Sudo Required

You need access to a sudo account to authorize and apply upgrades!

Every parachain runtime (the code in src/runtime/*) compiles to a single .wasm blob. The relay chain uses this blob to validate state transitions. "Forkless upgrades" simply mean replacing this WebAssembly blob with a new one.

The Parachain Upgrade Process

On a solo chain, you just call system.setCode. On a parachain, it's a two-step process because the relay chain must be notified:

1. Authorize: system.authorizeUpgrade - Notify the relay chain of the impending upgrade (requires the hash of the new runtime).
2. Apply: system.applyAuthorizedUpgrade - Upload the new code.

1. Compile your WASM Blob

Compile your runtime in release mode:

cargo build --release

The artifact will be at: target/release/wbuild/educhain-runtime/educhain_runtime.compressed.wasm

2. Obtain Runtime Hash

You need the Blake2b_256 hash of your new runtime file.

• Option A: Use this online tool.
• Option B: Upload the file in PolkadotJS UI (under system.authorizeUpgrade) to see the hash, then copy it.

3. Perform the Upgrade

PolkadotJS UISubstrate Frontend

1. Authorize: Call system.authorizeUpgrade with your new runtime hash.
   • Note: This is done on the parachain.
2. Wait: If using on-demand coretime, order a block to process the transaction. You should see the upgrade queued.
3. Apply: Call system.applyAuthorizedUpgrade and upload your compressed WASM blob (educhain_runtime.compressed.wasm).
   • Don't forget to order coretime if needed!

Prerequisites

• Clone the modified frontend template.
• Update src/config/development.json with your node details.

You can use the frontend template's upgrade function, but remember to still use the pallet interactor to authorize the upgrade first.