Looking at the Hugo version jump from 0.59.1 (released in September 2019) to the current latest version (0.147.5, released May 2025), you'll need to handle several major breaking changes that accumulated over 5+ years of development.
Hugo now prefers hugo.toml over config.toml as the primary configuration file name. While config.toml still works as a fallback, updating to hugo.toml aligns with current best practices and avoids potential conflicts in multi-framework setups.