Is this to produce binaries on the oldest possible distro so they'll run anywhere (symbol versioning etc.)? That being said, CentOS 5 hasn't received security

Is this to produce binaries on the oldest possible distro so they'll run anywhere (symbol versioning etc.)? That being said, CentOS 5 hasn't received security updates for year or so (or 2?), so maybe there's a security risk in continuing to rely on it? I guess CentOS 6 would be the oldest still supported distro.