# Runtime upgrade

### How to upgrade the chain

Prerequirements: Read substrate official documentation Read about webassembly and utilize "subwasm" Watch Alex's runtime migrations video: <https://www.youtube.com/watch?v=MQgDV37JrIY> Read about runtime migrations: <https://github.com/apopiak/substrate-migrations>

## Step 1

Add your changes to the code repository and make sure your pallets are included in the runtime. Increment the spec\_version by adding +1.

Compile your node

## Step 2

Go over modifed changes made to the storage and apply storage migrations to convert the old types to the new once in the `on_runtime_upgrade` function

Note: Failing to migrate important storage changes will have a negative effect on the chain Note: use logging to display what migrations kicked in

## Step 3

Verify that the compiled wasm file looks good with subwasm and srtool(<https://github.com/paritytech/srtool>).

## Step 4

Compile the node locally and use the current spec\_version that is deployed on chain(check polkadot.js for last upgrade in chainstate) Push the runtime upgrade either with as Sudo Call or as a democracy vote on your local instance. If all is well and the pallet's interact good after the upgrade, go ahead to the next step

## Step 5

Prep a release page for the node with the output from srtool and the hashes of the binary files, upload the wasm file aswell to the releases page.

## Step 6

Push the upgrade on-chain

### Links:

<https://develop--substrate-docs.netlify.app/how-to-guides/v3/storage-migrations/basics/> <https://docs.substrate.io/build/runtime-storage/> <https://docs.substrate.io/build/upgrade-the-runtime/>