Complex sentence: An initial, early version of the system, Mac OS X Server 1.0, was released in 1999; the first desktop version, Mac OS X 10.0, followed in March 2001.
Split into simpler sentences: An initial, early version of the system, Mac OS X Server 1.0, was released in 1999. The first desktop version, Mac OS X 10.0, followed in March 2001.