To make use of the JSONB features implemented in 9.4, it is required that you upgrade your existing PgSQL 9.3 cluster to 9.4+. I cover the basics on how to perform an in-place upgrade.
1. Add the PostgreSQL repo to apt:
echo "deb http://apt.postgresql.org/pub/repos/apt/ utopic-pgdg main" > /etc/apt/sources.list.d/pgdg.list
2. Install the repo’s key:
wget -q -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add