Overriding apt-get security check in Debian 9 (stretch) for Cloudera upgrade

I am trying to update Cloudera packages on several servers that have recently been upgraded to Debian 9 (stretch). The latest updates for Cloudera were for Debian 8 (jessie). The update/upgrade fails because Debian 9 thinks that Cloudera's GPG signature is invalid (not secure enough, I think?). Is there a way I get around this issue and force Debian to update/upgrade the packages, whether or not it dislikes the GPG key? Things I've tried that haven't worked: Adding [trusted=yes] to /etc/apt/sources.list, e.g.: deb [trusted=yes] http://archive.cloudera.com/cdh5/debian/jessie/amd64/cdh jessie-cdh5 contrib Telling (I think) apt-get to not worry about the authentication, e.g.: # apt-get --allow-unauthenticated update # apt-get --allow-unauthenticated upgrade Adding a file to /etc/apt/apt.conf.d with the following contents does not work. APT{ Get { AllowUnauthenticated "1"; }; }; What to do? EDITED: Here's the error I get from apt-get: Err:4 http://archive.cloudera.com/cdh5/debian/jessie/amd64/cdh jessie-cdh5 InRelease The following signatures were invalid: F36A89E33CC1BD0F71079007327574EE02A818DD Error: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.PackageKit': timed out Reading package lists... Done W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://archive.cloudera.com/cdh5/debian/jessie/amd64/cdh jessie-cdh5 InRelease: The following signatures were invalid: F36A89E33CC1BD0F71079007327574EE02A818DD W: Failed to fetch http://archive.cloudera.com/cdh5/debian/jessie/amd64/cdh/dists/jessie-cdh5/InRelease The following signatures were invalid: F36A89E33CC1BD0F71079007327574EE02A818DD