The old PAWS UI is being phased out (https://phabricator.wikimedia.org/T295043) We will be moving along with upstream to the JupyterLab interface (https://github.com/jupyterlab/jupyterlab). RetroLab (https://github.com/jupyterlab/retrolab) should you need the older interface. https://wikitech.wikimedia.org/wiki/PAWS/Additional_features has some instructions on how it can be accessed.

Thank you!