The classic notebook (Notebook V6) provides a document centered user experience. In comparison to JupyterLab which offers to provide a more traditional IDE experience. Users have argued that they already get other IDE like features in their Browsers, such as tabs, and so replicating that in a tab is redundant and provides possible performance overhead that they don’t want to pay. Additionally, many people prefer the look and feel of the classic notebook experience, which is where RetroLab came about to provide that simplistic document centered experience but now in lab. As part of JEP-79 it was proposed to provide this document centered experience but with the modular architecture and new API’s of Jupyter Server in Notebook V7. The guiding principles of Notebook V7 was to keep the core document centered experience, allow extensions, allow seamlessly swapping between lab and notebook. This was achieved by building of RetroLab as the basis, which was then deprecated when V7 was available.