How to troubleshoot API compatibility after a software release—don't rush to roll back.

Last week, I added a membership price field to an old order system. During the canary release, the new frontend looked fine, but the old mobile app used by customer service started showing "price is empty." At first, everyone wanted to roll back immediately, but I checked the access logs and API responses first. I discovered the issue wasn't in the database; rather, the old SDK's handling of the…