Complex sentence: This drew the attention and ire of AT&T, whose Unix System Labs subsidiary filed suit against BSDi in New Jersey in April of 1992, which they later amended to include The Regents of the University of California.
Split into simpler sentences: This drew the ire of AT&T, whose Unix System Labs subsidiary filed suit against BSDi in New Jersey in April of 1992. The suit was later amended to include The Regents of the University of California.