Upgrading Solaris 10 147440-1 to 147440-13 - Recomended OS Patchset or Oracle Critical Patch Update
Both the T4-4s has at least three zones each, so these will get patched at the same time.
The document has a few options:
Oracle Solaris Critical Patch Update (CPU) Patchsets - its been said that this references security issues and so forth
Recommended OS Patchsets for Oracle Solaris - this is what I usually use
Oracle Solaris Critical Patch Update (CPU) Patchsets
Oracle Solaris Update Patch Bundles - I guess I can forget this one