Complex sentence: All clamshell iBooks shipped with Mac OS 8.6 or 9.0 however all iBooks supported upgrading to Mac OS X v10.0--v10.3.9.
Split into simpler sentences: All clamshell iBooks shipped with Mac OS 8.6 or 9.0. However, all iBooks supported upgrading to Mac OS X v10.0--v10.3.9.