Technical debts: to find a way to improve the UX design and implement new components or screens step by steps without redesigning everything. I was aksked not to interfere with the end-users daily uses and habits to much. Consequently prioritization not only required my UX &UI expertises BUT flexibility to take into account the technical roadmap and its dependencies first. What I learned : It is much easier to make a screen and navigation look good when you can change everything at once... Progressive UX is a challenge that requires open mindness, forward thinking, negotiation skills and patience!