Rapid digitalisation over the past decade has transformed many aspects of work and daily life. The digital transformation is reshaping society, the labour market and the future of work. The COVID-19 pandemic, which has heavily impacted education and training, has accelerated this change. As outlined in the Digital Education Action Plan (2021-27) published by the EC: “digital technology, when deployed skillfully, equitably and effectively by educators, can fully support the agenda of high quality and inclusive education and training for all learners”. It can, in fact, facilitate more flexible and user-centred learning as well as engage learners in a more collaborative and creative learning experience, by helping both educators and learners access, create and share digital content. However, the type and design of digital technologies, as well as the digital pedagogy used, impact directly on the way learners are included from learning. When technology is referred to as “open source or FLOSS”, it means that people can modify and share the code because its design is publicly accessible. These technologies combine the free availability of technical artefacts and information with powerful community-based development and maintenance. They change the way we learn by fostering online communities, by enabling personalised learning experiences, by supporting the development of soft skills such as problem solving, collaboration and creativity, and by making learning fun. Open education has the potential to make educational systems more innovative and efficient and allows individuals to engage in new and more flexible ways of (lifelong) learning. These two components made of the integration of open education into EU education systems a policy objective, as argued in several EC plans and strategies.In this context, the “Promote Open Source Technologies in non-formal Adult Education” (Open-AE) project wants to promote open source technologies in non-formal adult education to support the digital upskilling of both educators and learners. It aims to build the capacity of training organisations to deliver high quality and relevant digital skills training to adults by improving staff competence on open source technologies.Open-AE achieved this by developing the Open-AE Curriculum addressed to trainers working in non-formal training sector to reinforce the digital skills of adult learners (e-facilitators). It consists of 18 modules mapped to DigCompEdu framework that cover transversal and specific digital skills by utilizing open education approach. Open-AE project produced an online Toolkit (https://open-ae.eu) that enables the implementation of the Curriculum by using several Open Educational Resources (OERs) and learning scenarios available on Open-AE Online Academy in 6 different languages. These project outputs were tested in four countries (Belgium Italy, Spain and Switzerland) through the Open-AE Course pilots which were completed by 89 e-facilitators in total. Based on the results of the piloting phase, the project produced the Guidelines for transferability and up-scaling of project results, aimed at both educators working in non-formal adult education sector and policymakers. The guidelines include recommendations for using the Open-AE methodology and mainstreaming the use of FLOSS in non-formal education and other fields. Open-AE project is the first structured attempt to promote the FLOSS culture as a whole in adult education. The high number of participants directly involved in the Open-AE training activities (twice as much as planned) and their overwhelmingly positive feedback on this experience, proved the effectiveness of Open-AE in improving teaching and digital skills of e-facilitators through a modular blended course for adult learners based on open source education.