The thing is that it's only the delta that is handled in UTC not the iso-8601-part so it will work just fine.
My first idé was to fix the interval calculations must like yours. The workaround for us was to set interval to always. We have local mirrors that can handle the load just fine even if we do updates every hour. -- 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/1824088 Title: unattended upgrade ran one day after schedule Status in apt package in Ubuntu: Triaged Bug description: I have noticed a strange behaviour in unattended upgrades. The host in question is scheduled to run upgrades on Mondays every second week. However, this week it ran upgrades on Tuesday instead (2019-04-09). This is the first time I’ve noticed this behaviour. I checked the logs in /var/log/apt/history.log* and I saw that worked as intended up until this week. Upgrades ran as expected on 2019-03-11 and 2019-03-25, which where both Mondays. The schedule was set with the line 'APT::Periodic::Unattended-Upgrade "14";' in the file /etc/apt/apt.conf.d/20auto-upgrades. Could it be daylight savings time that has caused skewing of the schedule? The server is located in Sweden and on 2019-03-31 we switched from CET to CEST. If the time diff is calculated with hours instead of calendar days passed, perhaps the missing hour on 2019-03-31 caused the scheduler to believe that on Monday 2019-03-08, two weeks (336 hours) had not yet passed. ADDITIONAL INFO Description: Ubuntu 16.04.6 LTS Release: 16.04 apt: Installed: 1.2.29ubuntu0.1 Candidate: 1.2.31 Version table: 1.2.31 500 500 http://se.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages *** 1.2.29ubuntu0.1 500 500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages 100 /var/lib/dpkg/status 1.2.10ubuntu1 500 500 http://se.archive.ubuntu.com/ubuntu xenial/main amd64 Packages unattended-upgrades: Installed: 0.90ubuntu0.10 Candidate: 0.90ubuntu0.10 Version table: *** 0.90ubuntu0.10 500 500 http://se.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages 500 http://se.archive.ubuntu.com/ubuntu xenial-updates/main i386 Packages 500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages 500 http://security.ubuntu.com/ubuntu xenial-security/main i386 Packages 100 /var/lib/dpkg/status 0.90 500 500 http://se.archive.ubuntu.com/ubuntu xenial/main amd64 Packages 500 http://se.archive.ubuntu.com/ubuntu xenial/main i386 Packages ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: apt 1.2.29ubuntu0.1 ProcVersionSignature: Ubuntu 4.4.0-142.168-generic 4.4.167 Uname: Linux 4.4.0-142-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.18 Architecture: amd64 Date: Wed Apr 10 09:06:49 2019 InstallationDate: Installed on 2017-12-28 (467 days ago) InstallationMedia: Ubuntu-Server 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801) SourcePackage: apt UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1824088/+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