The poster addresses the tension between theory and practice of research software development by contrasting sustainability requirements and practical necessities. The practice is related to the research project Edirom Online Reloaded, in which the legacy software Edirom Online is re-developed for making it more usable with present technology (e.g. modern browsers, touch devices) and also as sustainable as possible. Edirom Online is an open-source software for digital scholarly editions of musical works. Further goals of the re-development project are to establish a base for future development of the software and to strengthen the existing community. Organizational, institutional, and personal circumstances directly or indirectly challenge theoretical best practices, so ways have to be found to deal with the existing restrictions.