This version of Hardhat marks the debut of EDR (Ethereum Development Runtime), our new Rust-based runtime that is a complete rewrite of the original TypeScript-based Hardhat Network. This release lays a new long-term foundation for Hardhat's evolution over the coming year.
There are no functional changes, but there are some performance improvements across the board, which we’ll continue to expand in future updates.
Given the significance of this internal change, there’s a possibility of bugs. If you encounter any problems specific to this version, please report them by opening an issue. You should be able to downgrade to v2.20.1 without losing functionality if needed.
solidity-coverage out-of-memory issues
The solidity-coverage plugin works by heavily instrumenting the code, which sometimes causes OOM (out-of-memory) issues. This new version of Hardhat can, in certain cases, make those problems more likely.
If you run into this, you can fix it by using Node.js’s --max-old-space-size flag:
NODE_OPTIONS="--max-old-space-size=8192" npx hardhat coverageDropping support for Node.js v16
As part of this release, we are dropping support for Node.js v16. This version of Node.js reached its end-of-life in September of last year. You can learn more about our support guarantees here.