Re: BUG #16995: Need repository key to access old distributions from https://apt-archive.postgresql.org/

Re: PG Bug reporting form
> We are running into errors when installing Postgres 9.6 on Ubuntu. We
> noticed the distributions hosted on  `http://apt.postgresql.org` was
> returning 404 so we changed our installation scripts to refer to
> `https://apt-archive.postgresql.org/` instead as described here:
> https://www.postgresql.org/message-id/YBMtd6nRuXyU2zS4%40msg.df7cb.de
> 
> However, we are now running into the following error now:
> ```
> 16:40:34 WARNING: The following packages cannot be authenticated!
> 16:40:34   libpq5 libpq-dev pgdg-keyring postgresql-client-common
> postgresql-client-9.6
> 16:40:34   postgresql-common postgresql-9.6 postgresql-contrib-9.6
> ```

Which Ubuntu version is that?

Christoph