There is a similar situation where apt-get wants to remove packages when strict dependencies (equal version number) cannot be met. For example dovecot-core/dovecot-pop3d/dovecot-imapd.
After installing Ubuntu 16.04.3 LTS from the ISO, install the 3 packages from the release pocket: $ sudo apt install dovecot-imapd=1:2.2.22-1ubuntu2 \ dovecot-core=1:2.2.22-1ubuntu2 \ dovecot-pop3d=1:2.2.22-1ubuntu2 USN-3587-1 [1] wants dovecot-core to be upgraded to 1:2.2.22-1ubuntu2.7 Trying to upgrade dovecot-core to 1:2.2.22-1ubuntu2.7 will want to remove dovecot-imapd and dovecot-pop3d: $ sudo apt-get install --dry-run dovecot-core=1:2.2.22-1ubuntu2.7 Reading package lists... Done Building dependency tree Reading state information... Done Suggested packages: ntp dovecot-gssapi dovecot-sieve dovecot-pgsql dovecot-mysql dovecot-sqlite dovecot-ldap dovecot-imapd dovecot-pop3d dovecot-lmtpd dovecot-managesieved dovecot-solr The following packages will be REMOVED: dovecot-imapd dovecot-pop3d The following packages will be upgraded: dovecot-core 1 upgraded, 0 newly installed, 2 to remove and 171 not upgraded. Remv dovecot-imapd [1:2.2.22-1ubuntu2] Remv dovecot-pop3d [1:2.2.22-1ubuntu2] Inst dovecot-core [1:2.2.22-1ubuntu2] (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) Conf dovecot-core (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) Why? The only package that is *required* to be upgraded (because the USN specifies it, and because we currently treat USN package specs as binary packages), is dovecot-core. Apt's (simple) dependency solver figures it can upgrade that, but in doing so it breaks dovecot-imapd and dovecot-pop3d which need removing as a consequence. The workaround is to specify all 3 packages: $ sudo apt-get install --dry-run dovecot-core=1:2.2.22-1ubuntu2.7 \ dovecot-imapd=1:2.2.22-1ubuntu2.7 \ dovecot-pop3d=1:2.2.22-1ubuntu2.7 Reading package lists... Done Building dependency tree Reading state information... Done Suggested packages: ntp dovecot-gssapi dovecot-sieve dovecot-pgsql dovecot-mysql dovecot-sqlite dovecot-ldap dovecot-lmtpd dovecot-managesieved dovecot-solr The following packages will be upgraded: dovecot-core dovecot-imapd dovecot-pop3d 3 upgraded, 0 newly installed, 0 to remove and 171 not upgraded. Inst dovecot-pop3d [1:2.2.22-1ubuntu2] (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) [] Inst dovecot-imapd [1:2.2.22-1ubuntu2] (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) [] Inst dovecot-core [1:2.2.22-1ubuntu2] (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) Conf dovecot-core (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) Conf dovecot-pop3d (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) Conf dovecot-imapd (1:2.2.22-1ubuntu2.7 Ubuntu:16.04/xenial-security [amd64]) [1] https://usn.ubuntu.com/3587-1/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1788486 Title: apt behaviour when package with strict dependencies rules and version -gt in -updates than -security. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1788486/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs