The paper presents a research update on the AAL Call 4 EXO-LEGS project aimed at developing lower-body mobility exoskeletons to assist elderly persons to stay independent in their normal daily living activities for as long as possible. The important movement functionalities and key design issues to be included in the process are identified via specifically developed questionnaires and responses from a pan-European end user group set up as part of the project. The user requirements are used together with the recently published ISO safety requirements for personal care robots to perform targeted technical research in the areas of human gait analysis, modelling and simulation, mechanical engineering, embedded system design, and ergonomic user interfacing.