Along with an explanation of the SRU and update relationship, there's also this little snippet...
Changes to SRU and Update Naming Conventions
We're changing the naming convention of Update releases from a date based format such as Oracle Solaris 10 8/11 to a simpler "dot" version numbering, e.g. Oracle Solaris 11.1. Oracle Solaris 11 11/11 (i.e. the initial Oracle Solaris 11 release) may be referred to as 11.0.
SRUs will simply be named as "dot.dot" releases, e.g. Oracle Solaris 11.1.1, for SRU1 after Oracle Solaris 11.1.
— Solaris 11 SRU / Update relationship explained, and blackout period on delivery of new bug fixes eliminated (Solaris 11 Maintenance Lifecycle)
Woohooo!!! Almost everyone I've spoken to hated the old "marketing" method of naming Solaris releases. Solaris 11.0.12 is far easier to understand and explain than "Solaris 11 11/11 with SRU 12".