How to Manage Upgrades on Non-EVM Runtimes

Runtime upgrades are a core feature of modern, modular blockchains, allowing for seamless, forkless updates to the network's logic. Unlike Ethereum Virtual Machine (EVM) chains where upgrades often require hard forks or complex proxy patterns, non-EVM runtimes like Substrate's WebAssembly (Wasm) runtime or the Cosmos SDK's application-specific blockchain are designed for on-the-fly evolution. This capability enables developers to deploy new pallets (Substrate), modules (Cosmos), or consensus mechanisms without disrupting the network's state or requiring node operators to manually update client software. The upgrade is proposed, voted on via governance, and enacted automatically.

The technical foundation for forkless upgrades in Substrate is its WebAssembly-based execution environment. The runtime logic is compiled to a Wasm blob stored on-chain. When a valid upgrade proposal is approved, nodes switch to executing the new Wasm code. Key tools for developers include the sudo pallet for emergency upgrades in permissioned setups and the democracy or collective pallets for decentralized governance. The process typically involves: 1) Writing and testing new runtime logic, 2) Building a new runtime Wasm blob (target/release/wbuild/<runtime>/<runtime>.compact.wasm), 3) Submitting an authorizeUpgrade or setCode extrinsic via a governance proposal.

For Cosmos SDK chains, upgrades are managed through the x/upgrade module. The process is governance-led and involves submitting a SoftwareUpgradeProposal. A successful vote triggers an upgrade at a predetermined block height. Node operators must manually replace the binary before that height. The upgrade handler in app.go defines how the application migrates state between versions. A critical step is implementing the BeginBlock method from the upgrade module to execute migration logic. Unlike Substrate's on-chain Wasm, Cosmos upgrades require binary coordination, making community communication essential.

Managing upgrades requires rigorous testing to prevent chain halts. Use testnets like Rococo (Substrate) or public test chains (Cosmos) to simulate the upgrade process end-to-end. For Substrate, test the upgrade in a local try-runtime environment to verify state migrations. Key risks include: introducing a bug in the new runtime logic, flawed migration logic that corrupts state, or insufficient lead time for node operators to update binaries (in Cosmos). Always include comprehensive documentation for validators detailing the upgrade height and new binary version.

Successful runtime upgrades are a hallmark of mature blockchain projects. Examples include Polkadot's frequent runtime upgrades to add new features like nomination pools, or Cosmos Hub's Vega upgrade which implemented Interchain Security. By leveraging built-in upgrade mechanisms, developers can iteratively improve protocol economics, security, and functionality. The process underscores a shift from hard-fork coordination to programmable, community-governed blockchain evolution.

Unlike the EVM, where upgrade patterns like the Transparent Proxy or UUPS are standardized, non-EVM runtimes such as CosmWasm, Move, and FuelVM have their own native paradigms for code mutability. The core prerequisite is understanding your chain's specific state migration model. On CosmWasm, you upload a new code ID and migrate existing contracts to it. In Move, you publish new modules and use code::publish and code::migrate functions. Each approach has distinct implications for storage layout, authorization, and backward compatibility that must be planned for.

You must have a deep familiarity with your chosen runtime's module and package management. For instance, managing upgrades on a Solana program requires understanding the BPF loader and program-derived addresses (PDAs) for authority. On Aptos or Sui using Move, you need to grasp package publishing, the Move.toml manifest, and how the upgrade_policy dictates compatibility. Setting up a local testnet or devnet that mirrors mainnet behavior is essential for dry-running the entire upgrade lifecycle, from building and publishing the new bytecode to executing the migration function.

Security and access control are paramount. Before any upgrade, you must establish and secure the upgrade authority. This is often a multisig account or a decentralized governance module like Cosmos SDK's x/gov. You need to configure this authority in your contract's instantiation message or module manifest. Furthermore, you should implement and test a pause mechanism or migration controller within the contract logic itself, allowing authorized actors to halt operations during the upgrade window, preventing state corruption.

Finally, comprehensive testing cannot be overstated. You need a testing strategy that covers: unit tests for the new logic, integration tests that deploy and migrate a mock contract state, and simulation tests that replay mainnet state transitions. Tools like cargo-test for CosmWasm Rust contracts or the Move Prover for formal verification are critical. Always maintain a detailed upgrade checklist and rollback plan, including steps to verify storage compatibility and to redeploy the previous version if the migration fails.

Unlike the Ethereum Virtual Machine (EVM), where upgradeable contracts often rely on proxy patterns, non-EVM runtimes handle state and logic differently. For instance, Solana programs are typically immutable; "upgrades" involve deploying a new program and migrating state, a process managed by program-derived addresses (PDAs). On Cosmos SDK chains, upgrades are formalized through on-chain governance proposals that coordinate a halted network upgrade at a specific block height. These fundamental differences mean upgrade strategies are deeply integrated with each chain's consensus and execution model.

A common pattern across ecosystems is the use of migration scripts and versioned data structures. When deploying a new program version on Solana, you must write a script that deserializes the old account state, transforms it, and initializes new accounts for the upgraded program. Similarly, in Substrate-based chains (Polkadot), pallet logic can include migration hooks defined in a migrate function within the OnRuntimeUpgrade trait. This function executes automatically at the upgrade block, allowing for complex state transformations without manual intervention.

Security and governance are paramount. On permissionless Cosmos chains, a successful upgrade proposal requires a supermajority of staked tokens to vote "Yes," followed by validators manually upgrading their nodes. This process is slower but highly decentralized. In contrast, upgrade authority on Solana is often held by a program's upgrade authority keypair, which can be a multisig for security. A critical best practice is to thoroughly test state migrations on a testnet using a fork of mainnet state to avoid locking user funds or corrupting data.

Tooling and frameworks provide essential support. The Solana Program Library (SPL) offers utilities for managing program deployments. The Cosmos SDK's x/upgrade module handles the coordination logic for software upgrades. For Polkadot parachains, the Substrate FRAME system provides the scaffolding for runtime upgrades. Developers must familiarize themselves with these native tools, as generic Ethereum tooling like Hardhat or Foundry does not apply. Understanding chain-specific CLI commands for submitting governance proposals or deploying programs is a prerequisite.

Ultimately, managing upgrades on non-EVM chains is about planning for state continuity within immutable or versioned frameworks. Successful upgrades require: a clear migration path for all stored data, a secure and often decentralized governance mechanism to authorize the change, and comprehensive testing using chain-specific tooling to ensure a seamless transition for users and their assets.

Managing upgrades on non-EVM runtimes requires a fundamentally different approach than on Ethereum. While EVM chains rely on a single, well-defined virtual machine, runtimes like Solana's Sealevel, Cosmos SDK modules, and Polkadot's FRAME pallets are compiled to native code. This means upgrades are not just about new contract logic but can involve changes to the runtime's core logic, consensus rules, or state transition function itself. A robust testing strategy must therefore validate the entire node software, not just individual smart contracts.

The first pillar of a non-EVM upgrade strategy is comprehensive integration testing. This involves running a local testnet or a canary network (like Polkadot's Westend or a Cosmos test chain) with the new runtime binary. The goal is to simulate the upgrade process end-to-end, including governance proposals, on-chain voting, and the final runtime switch. Tools like Solana's local validator, the Cosmos SDK's simapp, and Polkadot's Zombienet are essential for creating these realistic test environments. You must test not only successful upgrades but also rollback procedures in case of a failed migration.

For runtime logic written in frameworks like Substrate's FRAME, unit and integration tests are written in Rust. A typical test suite for a new pallet includes verifying storage migrations, ensuring event emissions are correct, and checking that new extrinsics (transactions) behave as expected. For example, testing a Cosmos SDK module upgrade involves writing Go tests that instantiate the module's keeper with a mock context and assert state changes. These tests are run against the source code before any binary is compiled for a testnet.

State migration is a critical and high-risk component of non-EVM upgrades. Unlike EVM contracts where storage layout is managed by the contract, runtime upgrades can require migrating the entire chain's state to a new format. Your validation must include dry-run migrations on a snapshot of mainnet state. On Substrate, this is done using the try-runtime pallet's commands (on-runtime-upgrade). On Cosmos chains, you write migration scripts in Go and test them against exported state. The output must be verified for correctness and performance to avoid chain halts.

Finally, a successful upgrade requires coordinated validation from node operators. Before the mainnet proposal, you must provide the upgrade binary's hash, detailed instructions, and the results of your testnet trials. Operators will typically run the new binary in a shadow fork mode, processing real-time mainnet blocks to catch any unforeseen issues. This decentralized validation layer is crucial for networks like Cosmos and Polkadot, where independent operators must manually upgrade their nodes. Clear communication and proven tooling are as important as the technical tests themselves.

The primary takeaway is that upgrade management is a governance-first process. Unlike EVM chains where a single smart contract can be upgraded, non-EVM runtimes often require coordinated action at the protocol level. This involves submitting and passing governance proposals, which may require staking tokens for voting. For example, a Cosmos SDK chain upgrade is enacted via a SoftwareUpgradeProposal that must be voted on by validators. Understanding your chain's specific governance module—be it Cosmos' x/gov, Polkadot's OpenGov, or Solana's decentralized process—is the first critical step.

Your technical preparation should focus on testing and simulation. Before broadcasting a mainnet proposal, you must rigorously test the upgrade in a controlled environment. For Substrate-based chains, use a local testnet with the try-runtime pallet to simulate the state migration. On Solana, deploy and test the new program on devnet or testnet, ensuring all existing accounts and data are compatible. For Cosmos chains, use the simd tool to run a simulation of the proposal to catch any panics or state corruption before real funds are at risk. This phase is non-negotiable for security.

Finally, monitoring and post-upgrade validation are essential. Once the upgrade proposal passes and the chain halts at the target height, validators must switch to the new binary. Use chain-specific tools to monitor the rollout: Polkadot's PolkadotJS telemetry, Cosmos' cosmovisor logs, or Solana's validator metrics. Immediately verify that the chain is producing blocks, that core functionalities (like staking, transfers, and queries) are operational, and that the new runtime version is active. Document any issues and have a rollback plan, such as a community-agreed emergency downgrade proposal, ready in case of critical failures.