I am currently having a side project that requiring JSON Blob feature on PostgreSQL 9.4. But Ubuntu 14.04 only delivering PostgreSQL 9.3 on their repositories. Now I’ll posting step by step how to install or upgrade if you already using PostgreSQL 9.3 on ubuntu 14.04 to PostgreSQL 9.4.

Add PostgreSQL 9.4 repository and Import repository signing key, and update the package lists

sudo echo 'deb http://apt.postgresql.org/pub/repos/apt/ trusty-pgdg main' > /etc/apt/sources.list.d/pgdg.list

wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | \
  sudo apt-key add -

sudo apt-get update

Install PostgreSQL 9.4 and pgAdmin III

sudo apt-get install postgresql-9.4 pgadmin3

Check current clusters

pg_lsclusters

Stop PostgreSQL 9.4 cluster, drop it, and upgrade PostgreSQL 9.3 cluster to 9.4

sudo pg_dropcluster 9.4 main --stop
sudo pg_upgradecluster 9.3 main
sudo pg_dropcluster 9.3 main

Confirm only 9.4 cluster remains

pg_lsclusters