How to migrate from samba to samba3x, and revert if production is impacted

Issue

• In various cases, including for compatibility with Windows 7, Windows 2008R2 or later releases, migrating to Samba 3.3 or higher is required.
• The "samba" packages of Red Hat Enterprise Linux 5 contain Samba 3.0, Red Hat ships newer releases through the samba3x packages.
• How to backup existing samba configuration files and upgrade samba (samba-3.0) to samba3x
• Upgrade to latest version of samba (samba3x) is required for Red Hat Enterprise Linux 5.