A drone can be operated in the ‘in the ‘specific’ or the ‘certified’ category, when it does not meet the requirements laid out under the open category. See FAQ - How do I determine I fall under the ‘open’ category?
Regulatory reference: Article 4 and Article 20 of EU Regulation 2019/947; Annex part A and Article 5(1) of EU Regulation 2019/947, Parts 1 to 5 Annex of EU Regulation 2019/945.