Comment 19 for bug 1404783

These messages are only warnings, not errors. If you check the exit code (echo $?) after "apt-get update", you will see 0. So it is safe to upgrade the distribution despite these warnings. I have myself upgraded from Trusty to Xenial. Sure, it is unpleasant to see such warnings before upgrading of the distribution and it would be great if apt 1.0.7 or newer were backported to Trusty.