MDEbug is a full-day workshop held as part of MODELS 2018. Last year’s edition of the workshop (https://msdl.uantwerpen.be/conferences/MDEbug/2017/) brought together interested researchers to focus the research effort on debugging. Its objective was to define the scope of debugging within modelling, and work out a (preliminary) roadmap for future research. A paper summarizing the results of the workshop was published in the proceedings, which can be downloaded here. The intent of this second edition is to discuss new ideas in the identified areas. MDEbug will be a highly interactive workshop, stimulating discussion among researchers. We will have a keynote talk in the morning, followed by paper presentations. Afterwards, a number of discussion points will be decided upon and discussed in small, focused groups. We encourage submission of position papers that can stimulate the discussions, as well as more mature work on debugging, especially related to the notion of “stepping” in different modelling languages.