Added a note regarding PostgreSQL versions

README.md

@@ -3,7 +3,7 @@ Read Me
 
 1. About
 
-These Ansible roles allow you to install, from a deployment host, iRODS [4.2.0 - 4.2.8] on one or more CentOS 7.x x86_64 hosts. The iRODS role is compatible with both provider and consumer installation modes. PostgreSQL (9.6 on CentOS 7.x or 10.6 on CentOS 8.x) will be used to serve the iCAT catalogue. All firewalls should be stopped before attempting a deployment.
+These Ansible roles allow you to install, from a deployment host, iRODS [4.2.0 - 4.2.8] on one or more CentOS 7.x x86_64 hosts. The iRODS role is compatible with both provider and consumer installation modes. PostgreSQL (from 9.4 to 13 on CentOS 7.x or 10.6 on CentOS 8.x) will be used to serve the iCAT catalogue. All firewalls should be stopped before attempting a deployment.
 
 2. Ansible installation 
 
@@ -169,6 +169,7 @@ database_name: ICAT
 
 # Misc
 
+postgresql_version: from 9.4 to 13
 selinux_mode: enforcing
 ...
 ```