Upgrade postgresql 9.2 to 9.6 in CentOS 7 (bold steps)

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Install postgresql 9.6
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wget https://yum.postgresql.org/9.6/redhat/rhel-7.4-x86_64/pgdg-centos96-9.6-3.noarch.rpm
rpm -i pgdg-centos96-9.6-3.noarch.rpm

yum install postgresql96-server postgresql96-contrib
/usr/pgsql-9.6/bin/postgresql96-setup initdb

mv /usr/bin/pg_ctl{,-orig}
echo '#!/bin/bash' > /usr/bin/pg_ctl
echo '"$0"-orig "${@/unix_socket_directory/unix_socket_directories}"' >> /usr/bin/pg_ctl
chmod +x /usr/bin/pg_ctl

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Start importing/upgrading data to new server
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systemctl stop postgresql
# At this point both servers are stoped

# As Postgres user
su postgres
cd ~
/usr/pgsql-9.6/bin/pg_upgrade -v -b /usr/bin/ -B /usr/pgsql-9.6/bin/ -d /var/lib/pgsql/data/ -D /var/lib/pgsql/9.6/data/
exit

# Back to root user
# Rollback pg_ctl
mv -f /usr/bin/pg_ctl{-orig,}

#### APPLY OLD postgresql config params to postgresql-9.6 (pg_hba.conf, postgresql.conf) (manually), maybe use pgtune for postgresql.conf...

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START NEW SERVER AND DISABLE THE OLD
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systemctl start postgresql-9.6
systemctl enable postgresql-9.6
systemctl disable postgresql

# temporary
ln -s /usr/pgsql-9.6/bin/psql /usr/bin/psql --force
ln -s /usr/pgsql-9.6/bin/pg_dump /usr/bin/pg_dump --force

# Postgres user
su postgres
cd ~
./analyze_new_cluster.sh
exit

# back as root
# remove old postgresql
yum remove postgresql

# Export new path
echo 'export PATH=$PATH:/usr/pgsql-9.6/bin' >> /etc/bashrc

exit, SSH back to host and check if new path is ok for postgres commands

Finally decide if you want to remove the old postgres cluster (data folder)