Indeed, you seem to be using a mix of trusty and xenial packages. In particular, your libc6-dev 2.23-0ubuntu10 package comes from xenial, and your sa-compile 3.4.2-0ubuntu0.14.04.1 comes from trusty.
I'm afraid this is not supported and is likely to break, as indeed has happened. The sa-compile postinst will keep failing for any package upgrades you attempt. If you don't need sa-compile (it's part of spamassassin), then you should try to purge it with "sudo apt purge sa- compile". I will have to mark this bug as invalid, sorry, because of the mixed versions of packages you have. ** Changed in: spamassassin (Ubuntu) Status: Incomplete => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1803633 Title: package sa-compile 3.4.2-0ubuntu0.14.04.1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 25 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/spamassassin/+bug/1803633/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs