Vyper developers have launched vyupgrade, a tool designed to simplify the process of upgrading legacy smart contracts. Created by developer banteg, vyupgrade automatically rewrites older Vyper contracts to align with modern language versions and conducts comprehensive safety checks to ensure the updated code mirrors the original. The tool supports Vyper versions 0.2.1 through 0.4.3 and aims to extend compatibility to older versions, including those used in Uniswap V1. Vyupgrade addresses challenges posed by a 2023 Vyper compiler vulnerability that affected versions 0.2.15, 0.2.16, and 0.3.0, leading to exploits in DeFi protocols like Curve Finance. By automating the rewrite process and verifying code equivalence, vyupgrade provides a secure migration path from vulnerable to safe compiler versions. However, developers are reminded that while vyupgrade ensures bytecode-level equivalence, it does not replace the need for thorough audits to catch pre-existing logic bugs.