Upgrade 14 to 16.04: required dependency 'dpkg (>= 1.17.5ubuntu5.6)' is not installed. Help?

I am trying to update my Ubuntu from 14 to the latest Ubuntu 16.04. I am not able to upgrade and the following error messages comes up. What should I do?

required dependency 'dpkg (>= 1.17.5ubuntu5.6)' is not installed.