Malte's web agency started building web applications 24 years ago, using Symfony for the last 10 years. Dozens of these applications are still in operation and are developed further each year. You can imagine there is a lot of legacy code, and it grows with every new Symfony version, with every new PHP version, with growing developer experience and new development practices.

If you are like Malte and neither want to let this legacy code go moldy nor want to update it manually, have a peek into his 2021 toolbox for upgrading Symfony applications: tools for code style, feature determination, dependency management, batch replacements, static analysis and even semi-automatic upgrades for minor and major Symfony versions.