A key process in software product line (SPL) engineering is product derivation, which is the process of building software products from a base set of core assets. During product derivation, the components in both core assets and derived software products are modified to meet needs for different functionality, platforms, quality attributes, etc. However, existing software configuration management (SCM) systems do not sufficiently support the derivation process in SPL. In this paper, we introduce a novel SCM system that is well-suited for product derivation in SPL. Our tool, MoSPL handles version management at the component level via its product versioning and data models. It explicitly manages logical constraints and derivation relations among components in both core assets and derived products, thus enabling the automatic propagation of changes in the core assets to their copies in derived products and vice versa. The system can also detect conflicting changes to different copies of components in software product lines.