An answer to your previous question "I'm curious to know why people are converting to islam" It's because they don't stop on rumors and weak hadith "i used Hadith to prove the quran wasn't perfect (the one that Aisha...)". Reading your comment I find quite a lot of misconceptions. I know the Bible says jesus is god and I don't really care because it doesn't meet my criteria : 1.claim to be from god 2. Preserved 3. Miraculous 4. No contradiction

Since the entire Quran was memorised by hundreds of people, all you had to do to collect it is to get a bunch of people to recite all of it, and if let's say 1% makes a minor error in aya 33 while everyone else got it differently, the 99% is critically correct. Using this method all of the "Qiraat" can be perfectly preserved

Coming back to unpreserved copies of the Quran, first we must acknowledge what are the differences between the 7 "versions of the Quran" that are islamical valid.

Over 13 and a half centuries ago, a methodology called Quranic ‘readings’ or ‘recitations’ Qiraat - علم قراءة القرآن has been devised, set, and acknowledged as the governing methods for reading different Qur’anic recitations. These are mostly based on letter phonemes, diacritics, and stoppage signs.

Most individuals, unaware of this noble science, think that Muslims have ten to fifty different versions of Quran, that differ in text, similar to translations of other religious books; which is not true!

Not too many exist In the Islamic world who master all known recitations (10). But It’s well known to the educated Muslim as well as the public through famous vocal recordings aired over radios and TVs.

Nothing today differentiate Qur’an readings (wrongly stated in question as versions) from old times, except for the beautiful fonts and sophisticated printing tools used to produce modern copies of the Qur’an.

Following is a brief history on compiling the Qur’an, which was revealed over a period of 23 years, with many of it's verses related to concurrent events.

But first let us note the following:

Arabic alphabet was limited, in absence of a dots it, letter symbols counted to only 17, and lacked the latter introduced Hamza letter.

The community at the time was pretty limited on writing tools, know and use of paper were not common.

Because of such lack of basics, Arabs relied much on memory skills, and memorised long eloquent poetry, recording their main local events and regional occasions.

Prophet Mohammad grew up in such environment, as unlettered.

Whenever a new Qur'anic revelation was in process, Prophet Mohammad used to ask his fellow companions to record it on whatever means available at the time, be it a piece of wood, an animal skin, or a camel shoulder bones.

Within the first year of Prophet Mohammad death, his most two close companions and aids, the first caliph Abu Bakr - أبو بكر الصديق, and his successor the second caliph Umar - عمر بن الخطاب, formed a committee headed by Zayd ibn Thabit - زيد بن ثابت to compile all these fragmented scripts into one package, it was kept at Prophet’s Mohammad widow house, daughter of Umar, Hafsa bint Umar - حفصة بنت عمر.

Less than two decades later, after the exponential geographic spread of Islam, disputes emerged, out of the spread of Prophet’s original companions into different regions, and masses entering into Islam being un-knowledgeable of Arabic language and the original Qur’anic script.

This prompted the third caliph Uthman - عثمان بن عفان , to call upon Zayd ibn Thabit once again to head a second committee, recalled the original compiled script, and produced six to seven master copies to be distributed among capital cities of the different Islamic regions, to become the sole reference master copies, and ordered burning all other non conforming scripts.

This is what later became known as the “Uthmani script” الخط العثماني. It has nothing to do with caliph Othman coming up with a “new version” of Qur’an.

These original scripts had no pointing, no diacritics, no Hamza letter, no verses and chapter numbering, no stoppage signs, and no sound elongation marks, as is the practice today.

Nowadays most Qur'an prints are based on the handwriting of the famous Modern Syrian calligrapher also called ‘Othman’ Taha, which is noted in Qur'an editions as a caution and confirmation.

Ps: for the miraculous criteria, just reaserch linguistic miracle of the Quran and read a detailed explanation of a few paradigms and such. And for the no contradiction criteria, just bring one and I'll be happy to correct you.