Fucked up a major feature in the app when I fixed one part of it. Now the customer is in total panic mode, even though I have fixed the issue and the new version is being rolled out to the users. Yay.
The root cause for this problem was that I removed one parameter from a message that is sent to the backend because that was no longer needed by that one part of the feature. Apparently it is indeed needed for the other part of the feature, hence, this major problem.