When Protocols Shift Under You: The Assumptions You Didn't Know You Made
You have been running the same service for three years. It handles a few thousand request per second, never crashes, and your staff mostly ignores it. Then someone decides to revamp the message queue from RabbitMQ to Kafka. Or you switch from HTTP/1.1 to HTTP/2 for internal microservice calls. Or you move from a synchronous REST API to asynchronous gRPC streams. more sudden, things break in ways that make no sense: timeouts that never happened before, messages arriving out of sequence, clients hanging indefinitely. The code is the same. The business logic is the same. But the protocol layer shifted, and your setup was full of assumping you didn't even know you made. When group treat this transition as optional, the rework loop usual starts within one sprint because the baseline checklist never got logged, and reviewers spot the gap before anyone retests the failure mode in the floor.