TU Dortmund University has started the summer semester 2021 with a hybrid teaching mode with predominantly digital courses. Since the incidence in Germany has dropped sharply, the state of North Rhine-Westphalia allowed opening steps for teaching at universities in June. Nevertheless, protective measures still apply at TU Dortmund University. For example, a medical mask (OP or FFP2) must be worn in buildings throughout the campus. For employees, the TU Dortmund offers self-tests for home use and additionally scientifically supervised PCR pool tests on campus; if capacities are free, students can also use the offer as a supplement.