Neptune is willing to improve its security constantly like we showed in the past by using HTTPS on our website with Letsencrypt certificates. 

This time around we also changed our default repository server to use HTTPS. With the update to version 4.5.4 of the neptune-sourceslist package we changed the default repository to point to the https://download.neptuneos.com/ server. This also means that you need to have the package apt-transport-https installed to make it work. The update should automatically pull and install this package aswell.

The old proindi repository is available for approximately 1 month to ease the change and allow all users to upgrade to the new repository.