Christian Mosveen upgraded the React peer dependency to version 18 and above for the kartverket/kvib repository, focusing on modernizing dependencies and aligning the project with the latest React ecosystem. He approached this by updating configuration files, validating builds and tests to ensure compatibility, and documenting the change in a Markdown-based changeset to inform downstream consumers. His work centered on dependency management and frontend development, with careful attention to maintaining stability and avoiding regressions. By enabling support for React 18+ features, Christian improved the project’s maintainability and future readiness, though the scope was limited to a single feature without bug fixes.