Within a framework of study of the ecological impact of digital technology, this PhD project aims at understanding and analysing digital obsolescence. It aims to analyse software, hardware and middle-ware obsolescence, its technical aspects and its intertwining with non-technical ones such as economical, psychological, human and environmental obsolescence. The study will first focus on smartphones, whose rapid pace of development and replacement allows a better characterisation of digital obsolescence. The second object of our study is digital obsolescence within Debian, a widespread established operational system based on the Linux kernel, maintained by a large community that organises itself in a non profit organisation, following the principles of open source code, collaboration, free distribution and sharing for everyone. Finally, the study will dive into some alternative community networks that profoundly question existing technologies and are shaped and built with the central idea of care for ourselves, for each-other and for the environment.