Modernizing legacy applications, especially those built on Java or .NET, can be challenging due to issues like outdated dependencies, security vulnerabilities, and deployment targets. GitHub Copilot agent mode, combined with the GitHub Copilot app modernization extension for Visual Studio Code, provides an interactive, AI-assisted experience to streamline the process of upgrading and migrating Java projects, offering end-to-end support including .NET app modernization within Visual Studio. The tools help analyze codebases, generate upgrade plans, automate code changes, fix build issues, and validate tests, thus reducing manual effort and accelerating modernization. For Java projects, Copilot agent mode assists in upgrading to newer JDK versions, adjusting dependencies, and preparing applications for cloud deployment, particularly to Azure. It also includes comprehensive CVE scanning to ensure security compliance and offers a guided workflow to validate changes and enhance test coverage. This modernization approach, as detailed by Andrea Griffiths, a Senior Developer Advocate at GitHub, aims to make advanced technologies more accessible and efficient for developers, ultimately transforming legacy projects into cloud-ready applications.