Modeling languages started as key elements for sketching and documenting software-intensive systems. Today, we often recognize a discrepancy between design models concentrating on the desired behaviour of a system and its real world correspondents reflecting deviations taking place at runtime. In order to close this gap, design models must not be static elements, but evolutionary ones. However, this requires a new generation of modeling languages equipped with an explicit runtime perspective incorporating operational data. Efficiently developing such modeling languages with novel language engineering methods is our quest in the research laboratory CDL-MINT (https://cdl-mint.se.jku.at).