I dont think this is a bug. The wording says what the issue is. The Key used is only sha1 which is considered too weak. The ones using that old Keys should fix their repos and make proper signing.
-- 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: message "The repository is insufficiently signed by key (weak digest)" is poorly worded 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 : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp

