An effort to update the CDIO Standards from version 2.1 to 3.0 was started in 2017 (Malmqvist et al., 2017) and further outlined in 2019 (Malmqvist et at., 2019). The aims were to incorporate external changes to the context of engineering education, to address criticism that had been raised against earlier versions of the standards, and to establish an extendable CDIO framework architecture. The work has resulted in that the original twelve CDIO standards, from now on named “core” CDIO standards, will be complemented by “optional” CDIO standards, that codify additional educational best practices that have been developed within the CDIO community in the same format as the original CDIO standards. Eleven optional standards have been proposed (Malmqvist et al., 2019). This paper accounts for the elaboration of the subset of the proposed optional standards that were recommended for further development by the CDIO Council in November 2019. These recommended optional standards are presented as full texts, i.e., including descriptions, rationale and rubrics. The described optional standards are: Sustainable development, Simulation-based mathematics, Engineering entrepreneurship and Internationalization & mobility.
