Ok, I think I've got this, here's the results on silo 56: The following packages will be upgraded: libaccounts-qt5-1 libonline-accounts-client1 libsignon-extension1 libsignon-plugins-common1 libsignon-qt5-1 qml-module-ubuntu-onlineaccounts qml-module-ubuntu-onlineaccounts-client qtdeclarative5-accounts-plugin qtdeclarative5-online-accounts-client0.1 signon-plugin-oauth2 signon-plugin-password signond 12 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 407 kB of archives. After this operation, 2,048 B of additional disk space will be used. Get:1 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main libaccounts-qt5-1 armhf 1.14+15.04.20150930-0ubuntu1 [28.7 kB] Get:2 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main libonline-accounts-client1 armhf 0.7+15.04.20151009.2-0ubuntu1 [13.7 kB] Get:3 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main libsignon-extension1 armhf 8.58+15.04.20151001-0ubuntu1 [18.8 kB] Get:4 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main libsignon-plugins-common1 armhf 8.58+15.04.20151001-0ubuntu1 [16.2 kB] Get:5 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main libsignon-qt5-1 armhf 8.58+15.04.20151001-0ubuntu1 [54.3 kB] Get:6 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main qml-module-ubuntu-onlineaccounts armhf 0.6+15.04.20151007-0ubuntu1 [47.7 kB] Get:7 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main qml-module-ubuntu-onlineaccounts-client armhf 0.7+15.04.20151009.2-0ubuntu1 [6,988 B] Get:8 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main qtdeclarative5-accounts-plugin armhf 0.6+15.04.20151007-0ubuntu1 [1,390 B] Get:9 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main qtdeclarative5-online-accounts-client0.1 armhf 0.7+15.04.20151009.2-0ubuntu1 [1,462 B] Get:10 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main signon-plugin-oauth2 armhf 0.23+15.04.20151001.1-0ubuntu1 [52.4 kB] Get:11 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main signond armhf 8.58+15.04.20151001-0ubuntu1 [153 kB] Get:12 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main signon-plugin-password armhf 8.58+15.04.20151001-0ubuntu1 [11.9 kB] Fetched 407 kB in 4s (99.6 kB/s) So it's only installed packages from silo 56, nothing from vivid and nothing from stable snapshot ppa. $ adb shell apt-cache policy signond signond: Installed: 8.58+15.04.20151001-0ubuntu1 Candidate: 8.58+15.04.20151001-0ubuntu1 Version table: *** 8.58+15.04.20151001-0ubuntu1 0 1100 http://ppa.launchpad.net/ci-train-ppa-service/landing-056/ubuntu/ vivid/main armhf Packages 100 /var/lib/dpkg/status 8.57+15.04.20150616-0ubuntu1 0 50 http://ppa.launchpad.net/ci-train-ppa-service/stable-snapshot/ubuntu/ vivid/main armhf Packages 8.57+15.04.20150204.1-0ubuntu1 0 50 http://ports.ubuntu.com/ubuntu-ports/ vivid/main armhf Packages this shows the correct silo pinned at 1100, and the stable ppa & vivid itself pinned at 50, which is beneath locally installed packages, so they won't be installed unless a dependency specifically brings them in.