# As root
# Add pg repo if not already established 
sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ $(lsb_release -cs)-pgdg main" > /etc/apt/sources.list.d/pgdg.list'
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | apt-key add -
apt update
# Tweak needed packages
apt install postgresql-9.6 postgresql-client-9.6 postgresql-contrib-9.6 postgresql-plpython3-9.6 postgresql-server-dev-9.6 postgresql-9.6-plr postgresql-9.6-mysql-fdw
pg_dropcluster 9.6 main --stop
pg_upgradecluster -m upgrade 9.5 main
pg_dropcluster 9.5 main