I'm having the same issue with the google talk plugin, remmina, shutter, and variety:
W: gpgv:/var/lib/apt/lists/ppa.launchpad.net_peterlevi_ppa_ubuntu_dists_xenial_InRelease: The repository is insufficiently signed by key 876E675CB1AABA3494F27BA6C45A53C1A546BE4F (weak digest) W: gpgv:/var/lib/apt/lists/partial/dl.google.com_linux_talkplugin_deb_dists_stable_Release.gpg: The repository is insufficiently signed by key 4CCA1EAF950CEE4AB82976DCA040830F7FAC5991 (weak digest) W: gpgv:/var/lib/apt/lists/ppa.launchpad.net_remmina-ppa-team_remmina-next_ubuntu_dists_xenial_InRelease: The repository is insufficiently signed by key 04E38CE134B269B9F38F82EE8A993C2521C5F0BA (weak digest) W: gpgv:/var/lib/apt/lists/ppa.launchpad.net_shutter_ppa_ubuntu_dists_xenial_InRelease: The repository is insufficiently signed by key 5017D4931D0ACADE295B68ADFC6D8D9D009ED615 (weak digest) W: Failed to fetch http://dl.google.com/linux/talkplugin/deb/dists/stable/Release No Hash entry in Release file /var/lib/apt/lists/partial/dl.google.com_linux_talkplugin_deb_dists_stable_Release, which is considered strong enough for security purposes E: Some index files failed to download. They have been ignored, or old ones used instead. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/1558331 Title: After upgrading to apt 1.2.7 in Xenial, PPAs and most other third- party repositories become unusable with "The repository is insufficiently signed by key (weak digest)" Status in apt package in Ubuntu: Confirmed Bug description: The title pretty much says it all. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1558331/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
