Today I found out that my phpMyAdmin installation over apache2 and Ubuntu 13.10 was broken. The error was straight forward: “JSON extension is missing”.
Okay, but how can it be gone?
I recently updated my Ubuntu installation from 13.04 to 13.10. Turns out that it somehow breaks the PHP JSON extension.
The fix is very simple, run
sudo apt-get install php5-json
sudo service apache2 restart