akonadi-backend-postgresql software package provides PostgreSQL storage backend for Akonadi, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install akonadi-backend-postgresql
akonadi-backend-postgresql is installed in your system.
Make ensure the akonadi-backend-postgresql package were installed using the commands given below,
$ sudo dpkg-query -l | grep akonadi-backend-postgresql *
You will get with akonadi-backend-postgresql package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | Miscellaneous |
| Package | akonadi-backend-postgresql |
| Version | 4:15.12.3-0ubuntu6 |
| Description | PostgreSQL storage backend for Akonadi |
| Sub Section | Misc |