uni-heidelberg.de OSM tile server no longer active

The maps tileLayer from uni-Heidelberg link is no more working:

diaspora/app/assets/javascripts/app/helpers/locations.js

Line 17 in 4c74136

    
           return L.tileLayer("http://korona.geog.uni-heidelberg.de/tiles/roads/x={x}&y={y}&z={z}", {

See announcement here:
http://k1z.blog.uni-heidelberg.de/2019/02/08/the-future-of-openmapsurfers-tiles/

What consequences has this? Should the be removed or changed?

This means, Maps configured for this tile supplier won't work. What means, it should be changed.

Should Heidelberg- Tiles be removed completely or is it better to let Podmins choose?
The alternative to Heidelberg seems now to need a login and to provide an API token.
Any comments?