We have implemented and closed user story X but found out later that the implementation is too slow and we need to improve performance. I think it was a mistake not to have acceptance criteria for performance in the first place but it happened and the question is what to do now.
We can theoretically do one of these things:
- Reopen the user story (we use JIRA and it is technically not a problem), add acceptance criteria and let the development "fix" the software.
- Create a new user story, like "make the user experience of feature X smoother".
- Create something that is not a user story (in JIRA, probably an issue of type "Task").
Is there a best practice telling what to do in such case?