Road to Replay: Safely Upgrading Payment Workflows at Scale with Block

Upgrading long-running, mission-critical workflows in production is one of the hardest challenges in distributed systems, especially when those workflows move money.

In this session, Daniel Skarbek, Senior Staff Software Engineer from Block, shares how the team has designed and upgraded core payment ledger workflows using Temporal, supporting a system that processes millions of transactions daily with strict reliability and correctness requirements. You’ll learn how Block implemented a dispatcher pattern for workflow versioning and how this approach enables safe upgrades even while workflows are actively running.

This webinar dives into the technical tradeoffs, upgrade strategies, and common pitfalls teams face when evolving long-lived workflows in production, and shows how Temporal’s durability and visibility make it possible to coordinate complex payment flows with confidence.

Key takeaways:
- Implement a dispatcher pattern for workflow versioning to safely route traffic between old and new workflow versions.
- Upgrade long-running workflows in production without breaking in-flight executions or compromising data integrity.
- Understand when built-in workflow versioning tools are enough, and when custom approaches are required.
- Avoid common pitfalls in workflow upgrades, including schema changes, behavior drift, and replay-related surprises.

---

Temporal is the simple, scalable, open source way to write and run reliable cloud applications. 

Learn more
Blog: https://temporal.io/blog
How Temporal Works: https://temporal.io/how-temporal-works
Community Slack: https://temporal.io/slack

Developer resources
Docs: https://docs.temporal.io
Courses: https://learn.temporal.io/courses
Support forum: https://community.temporal.io