How does Scala support zero-downtime rolling upgrades in distributed systems?

Scala systems achieve zero-downtime upgrades using stateless services, backward-compatible APIs, and progressive traffic shifting.

Zero-downtime deployments rely on rolling updates in Kubernetes or service mesh environments. Scala services are designed to be stateless, allowing instances to be replaced incrementally. Backward and forward compatibility ensures new and old versions can coexist. Feature flags and canary deployments reduce risk. Event-driven systems decouple service dependencies, allowing independent upgrades.