During software evolution a collection of related artifacts with different representations are created. Some of these are composed of structured data (e.g., analysis data), some contain semi-structured information (e.g., source code), and many include unstructured information (e.g., text). Research efforts exist that are trying to extract, represent, and analyze the unstructured information in software. Information retrieval (IR) techniques are used quite successfully in the past years to represent and extract textual information from software artifacts, with application to many maintenance tasks. This working session will focus on the state on the art in the application of IR-based techniques to support software maintenance activities. The session aims to identify the main research and practical issues in the field, to determine future work directions, and to foster collaborations among the participants.