Oh, this is slightly embarrassing: THe reason it failed is that I forgot to update apt-transport-https in trusty and xenial.
After upgrading apt-transport-https, auth.conf.d support is working correctly in both 1.0.1ubuntu2.21 in trusty-proposed, and 1.2.30 in xenial-proposed.
Oh, this is slightly embarrassing: THe reason it failed is that I forgot to update apt-transport-https in trusty and xenial.
After upgrading apt-transport- https, auth.conf.d support is working correctly in both 1.0.1ubuntu2.21 in trusty-proposed, and 1.2.30 in xenial-proposed.