Migrating a mature app to Compose Multiplatform can become a multi-year bet whose value only appears at the end. We took a different approach: every step had to deliver value to Android, even if the migration never reached iOS. I'll share how we migrated a 14-year-old app with 80 screens while continuing to ship features. We defined migration KPIs and built a custom Gradle plugin to track them automatically, helping us identify bottlenecks and prioritize work. I'll also cover our architectural, testing, and AI-assisted refactoring decisions. Key takeaways: - Choose KPIs that reveal real migration progress. - Automate tracking to identify bottlenecks. - Make every migration step deliver standalone value for current codebase.