Yannis Coulibaly expanded the subscription status tracking in the supabase/stripe-sync-engine repository by introducing a new 'paused' state to the Stripe subscription_status enum. This schema evolution, implemented using SQL and database management skills, enables the system to represent temporarily inactive subscriptions, improving both billing accuracy and lifecycle management. Yannis approached the change through careful schema modification and Git-based change management, ensuring analytics and revenue recognition processes could now account for paused states. While the work focused on a single feature without bug fixes, it demonstrated a methodical approach to database evolution and integration with Stripe’s subscription infrastructure.