How Do Developers Use Migration Guides? A Case Study of Log4j

Migration guides are a form of software documentation to help clients address breaking changes introduced during library version updates. While prior studies have examined documentation such as release notes, API reference manuals, and patch notes, research that focuses specifically on migration guides remains limited. Improving the usability and coverage of migration guides is essential for supporting developers in resolving breaking changes efficiently; however, the current state of their provision and use is not yet well understood.To bridge this gap, we first investigate the availability of migration guides for libraries known to introduce incompatibilities, using a dataset that collects real-world breaking changes. Then, we conduct an in-depth case study of Log4j, a library that underwent major disruptive updates in the past, to empirically analyze how developers reference and utilize its official migration guide in practice.Our findings clarify the current provision status of migration guides and shed light on how they are actually used in real-world development environments. These insights provide a foundation for improving migration guide design and for developing automated assistance tools that support developers in handling breaking changes.