  Context and motivation: In this industry-academia collaborative project, a
team of researchers, supported by a software architect, business analyst, and
test engineer explored the challenges of requirement variability in a large
business software development company. Question/problem: Following the design
science paradigm, we studied the problem of requirements analysis and tracing
in the context of contractual documents, with a specific focus on managing
requirements variability. This paper reports on the lessons learned from that
experience, highlighting the strategies and insights gained in the realm of
requirements variability management. Principal ideas/results: This experience
report outlines the insights gained from applying design science in
requirements engineering research in industry. We show and evaluate various
strategies to tackle the issue of requirement variability. Contribution: We
report on the iterations and how the solution development evolved in parallel
with problem understanding. From this process, we derive five key lessons
learned to highlight the effectiveness of design science in exploring solutions
for requirement variability in contract-based environments.
