Last night, we updated our web service for a high-value customer after some hard work adding some badass new features. We thought it was a job well done and they would be happy.
This morning we found out we'd broken no less than 4 existing features, two of which were found before we fixed them. They could be counted as 5 if you consider two different PDFs as separate features.
And yes, all of our tests passed.
What's the most you've ever caused in one update?