It has long been known that variant copies of the Koran exist, including some found in 1972 in a paper grave at Sa'na in Yemen, the subject of a cover story in the January 1999 Atlantic Monthly. Before the Yemeni authorities shut the
door to Western scholars, two German academics, Gerhard R Puin and H C Graf von
Bothmer, made 35,000 microfilm copies, which remain at the University of the Saarland. Many scholars believe that the German archive, which includes photocopies of manuscripts as old as 700 AD, will provide more evidence of variation in the Koran.
It’s interesting to see another article on the subject. For a summary of other issues with the Koran’s transmission, see here.