Comment 19 for bug 1878723

FYI, version 0.11-4ubuntu2.5 was recently released. If you are still experiencing this issue, the following steps will correct it:

1. Remove the postinst file from the affected package (version 0.11-4ubuntu2.1):
sudo rm /var/lib/dpkg/info/libjson-c2\:amd64.postinst

2. Re-run the package configure step to correct its half-installed status:
sudo dpkg --configure -a

3. Update the package list from the repository:
sudo apt update

4. Upgrade the affected package to the latest version:
sudo apt install libjson-c2

5. Reboot to activate the new package:
sudo reboot

Any user running a version of the libjson-c2 package not equal to 0.11-4ubuntu2.1 will not have to go through these steps and updating the package to the new version will be done the normal way; either through unattended-updates or manual apt upgrade.