Quran is the word of god which was memorized and recited by Mohammed's(peace be upon him) companions and written in a complete book later on without any changes to it original version. There is only one version and no other exists anywhere.All other religious scriptures have been altered by man and changed over time except the Quran. If you do not believe that, ask any arabic writer to write anything that comes even close to scripture of the Quran and all of them will fail to produce it.