The 3DCityDB-Tools plug-in for QGIS enables users to connect to the open-source 3D City Database (3DCityDB) 4.x, load CityGML 1.0 and 2.0 data, and structure it as GIS layers within QGIS. The plug-in simplifies interaction with the complex structure of the 3DCityDB 4.x by providing a GUI-based tool and a server-side package for seamless data retrieval and management from QGIS. With the release of the CityGML 3.0 conceptual data model in 2021, the 3D City Database has been updated to version 5.0, introducing several changes to support the new characteristics of CityGML 3.0 and a significant redesign and restructuring of the database schema. However, the current 3DCityDB-Tools plug-in for QGIS does not support the latest CityGML and 3DCityDB versions. This paper presents the findings and experiences gathered to modify the plug-in’s server-side architecture to cope with the new 3DCityDB 5.0. Similar to what already happens with the current plug-in version, the proposed new approach enables the generation of GIS layers following the Simple-Feature-for-SQL model, optimising query performance and improving attribute management. The resulting vector-based layers can be seamlessly imported into QGIS, allowing for interaction between QGIS and the underlying CityGML data stored in the latest version of the 3DCityDB.