Short answer
No. There is one Qur'an, recited in a small number of approved ways. The Prophet (ﷺ) said it was revealed to be recited in seven modes, called ahruf. He said this when two companions recited the same chapter differently, and he approved both. The modes were given as an ease, so each person could recite in the way easier for him. Today most Muslims recite the reading called Hafs. Many in North and West Africa recite Warsh. The two differ in vowels, sounds and a small number of words. In the first chapter, one reads "Master of the Day of Judgment" and the other "King". Both are true of God (﷾). No reading contradicts another, and none changes a belief: not about God (﷾), not about Jesus, not about the hereafter. Islam's answer is one Qur'an, taught by the Prophet (ﷺ) himself.
Full explanation
What the Prophet (ﷺ) said
Umar, a companion of the Prophet (ﷺ), heard another companion recite a chapter differently from the way he had learned it. He brought the man to the Prophet (ﷺ). The Prophet (ﷺ) had each man recite, and said of both that this was how it was revealed. He then said the Qur'an was revealed to be recited in seven modes, so they should recite whichever mode was easier for them. Al-Bukhari is a collection of sound hadith, the reports of the Prophet's (ﷺ) words and actions. In another report there, the Prophet (ﷺ) says he kept asking Gabriel for more until the Qur'an was recited to him in seven modes.
Umar heard Hisham ibn Hakim recite Surat al-Furqan differently from the way he had learned it and brought him to the Prophet (ﷺ). The Prophet had each recite, said of both readings that the surah was revealed that way, and said the Qur'an was revealed to be recited in seven ways, so recite whichever is easier.
Ibn Abbas reports that the Prophet (ﷺ) said Gabriel first recited the Qur'an to him in one mode, and that he kept asking for more until Gabriel recited it in seven modes.
An example of a difference
In the Hafs reading, the fourth verse of the first chapter calls God maaliki, with a long a: Master of the Day of Judgment. In the Warsh reading the same word is read maliki, with a short a: King of the Day of Judgment. Uthman was the third caliph (leader of the Muslims) after the Prophet (ﷺ). He had copies of the Qur'an made and sent to the provinces. In those copies the two are one written word. The early script did not mark the long vowel. Both describe the same God (﷾), and each is true of Him. Most differences between the readings are of this kind, or smaller: a vowel, a dot on a letter, or the way a sound is pronounced.
“Master of the Day of Judgment.”
Compares the Hafs and Warsh transmissions of the Qur'an in detail. Finds that nearly all their differences are in vowels and in the dots that tell apart letters of the same shape, and that very few make any significant difference to the meaning. Concludes that the transmission of the Qur'an after Muhammad (ﷺ) was essentially static: there was a single text, and nothing significant could be taken out of it or put into it.
Anas reports that Hudhayfa ibn al-Yaman, alarmed at how the soldiers of Syria and Iraq differed in reciting the Qur'an, urged Uthman to save the community before it differed over its Book as the Jews and Christians had. Uthman borrowed the collected sheets kept by Hafsa, had Zayd ibn Thabit and three men of Quraysh copy them, telling the three that wherever they differed with Zayd they should write in the dialect of Quraysh, in which the Qur'an was revealed, returned the sheets to her, sent a copy to every province, and ordered all other written Qur'anic material to be burned.
What a detailed comparison found
Adrian Brockett, an academic writing in 1988, compared Hafs and Warsh in detail. He found that very few of their differences change the meaning at all. He concluded that there was a single text of the Qur'an. He also concluded that nothing significant was taken out of it or put into it after Muhammad (ﷺ).
Compares the Hafs and Warsh transmissions of the Qur'an in detail. Finds that nearly all their differences are in vowels and in the dots that tell apart letters of the same shape, and that very few make any significant difference to the meaning. Concludes that the transmission of the Qur'an after Muhammad (ﷺ) was essentially static: there was a single text, and nothing significant could be taken out of it or put into it.
How the readings came about
The Prophet (ﷺ) let each companion recite in whichever of the revealed modes was easier for him. So each companion recited as he had been taught, and taught his students the same way. As companions settled in Makkah, Madinah, Kufa, Basra and Damascus, each city came to recite as its teachers did. A reading is named after a master reader known for one such way of reciting, handed down with its chain. Nafi' of Madinah is one: Warsh passed on his reading. Asim of Kufa is another: Hafs passed on his. Ibn Mujahid named seven such readers in the tenth century. Later scholars, Ibn al-Jazari foremost among them, recognised three more, making the ten readings taught today.
Umar heard Hisham ibn Hakim recite Surat al-Furqan differently from the way he had learned it and brought him to the Prophet (ﷺ). The Prophet had each recite, said of both readings that the surah was revealed that way, and said the Qur'an was revealed to be recited in seven ways, so recite whichever is easier.
Ibn al-Jazari gives the reading of Nafi' of Madinah in the transmissions of Qalun and Warsh. In the verse where Moses answers Pharaoh (17:102), he records that al-Kisa'i reads "I know" (la-qad 'alimtu) where the other readers have "you know" (la-qad 'alimta). In 49:6, and twice in 4:94, Hamza, al-Kisa'i and Khalaf read "make sure" (fa-tathabbatu) where the others have "verify" (fa-tabayyanu).
Ibn al-Jazari sets out the chains of the reading of Asim of Kufa (d. 745 CE), which Hafs passed on. Hafs learned it from Asim. Asim learned from Abu Abd al-Rahman al-Sulami, Zirr ibn Hubaysh and Abu Amr al-Shaybani, who learned from Abdullah ibn Mas'ud. Al-Sulami and Zirr also learned from Uthman and Ali, and al-Sulami from Ubayy ibn Ka'b and Zayd ibn Thabit. These companions learned it from the Prophet (ﷺ). Asim led the teaching of the Qur'an in Kufa after al-Sulami. Ibn al-Jazari lists dozens of routes by which the reading reached him.
Shows how the Baghdad scholar Ibn Mujahid (d. 936 CE) chose seven readers of the Qur'an as the standard ones in the early tenth century, and how that choice came to be accepted.
The standard classical work on the readings. It lays down that a reading is accepted as Qur'an only if it fits the written form of one of Uthman's copies, is sound Arabic, and has a sound chain of transmission back to the Prophet (ﷺ). It notes that the seven readers chosen by Ibn Mujahid are not the same thing as the seven ahruf of the hadith, and that the readings which meet these conditions are all accepted as Qur'an.
Two sides of one truth
Some differences add meaning without changing it. When Moses shows Pharaoh the signs, most readings have Moses say: you know well that these were sent down by none but the Lord of the heavens and the earth. In the reading of al-Kisa'i, Moses says: I know well. Pharaoh knew the truth he denied, and Moses was certain of it. Both are true. In another verse, believers who hear news from a wicked person are told to verify it; in other readings they are told to make sure of it. The duty is the same in either wording.
“Moses said, "Thou knowest well that these things have been sent down by none but the Lord of the heavens and the earth as eye-opening evidence: and I consider thee indeed, O Pharaoh, to be one doomed to destruction!"”
“O ye who believe! If a wicked person comes to you with any news, ascertain the truth, lest ye harm people unwittingly, and afterwards become full of repentance for what ye have done.”
Ibn al-Jazari gives the reading of Nafi' of Madinah in the transmissions of Qalun and Warsh. In the verse where Moses answers Pharaoh (17:102), he records that al-Kisa'i reads "I know" (la-qad 'alimtu) where the other readers have "you know" (la-qad 'alimta). In 49:6, and twice in 4:94, Hamza, al-Kisa'i and Khalaf read "make sure" (fa-tathabbatu) where the others have "verify" (fa-tabayyanu).
The seven modes and the seven readings
The seven modes of the hadith are not the same as the seven readings named later. Those seven readers were chosen by the Baghdad scholar Ibn Mujahid in the early tenth century, from among the readings then taught. Muslim scholars differ over exactly what the seven modes were. They agree on the test for every accepted reading. It must fit the written form of Uthman's copies. It must also go back to the Prophet (ﷺ) through a sound chain of reciters.
Shows how the Baghdad scholar Ibn Mujahid (d. 936 CE) chose seven readers of the Qur'an as the standard ones in the early tenth century, and how that choice came to be accepted.
The standard classical work on the readings. It lays down that a reading is accepted as Qur'an only if it fits the written form of one of Uthman's copies, is sound Arabic, and has a sound chain of transmission back to the Prophet (ﷺ). It notes that the seven readers chosen by Ibn Mujahid are not the same thing as the seven ahruf of the hadith, and that the readings which meet these conditions are all accepted as Qur'an.
Anas reports that Hudhayfa ibn al-Yaman, alarmed at how the soldiers of Syria and Iraq differed in reciting the Qur'an, urged Uthman to save the community before it differed over its Book as the Jews and Christians had. Uthman borrowed the collected sheets kept by Hafsa, had Zayd ibn Thabit and three men of Quraysh copy them, telling the three that wherever they differed with Zayd they should write in the dialect of Quraysh, in which the Qur'an was revealed, returned the sheets to her, sent a copy to every province, and ordered all other written Qur'anic material to be burned.
One Qur'an in every mosque
Because every accepted reading is the Qur'an, a Muslim may recite any of them in prayer. A Muslim may also pray behind an imam (the man who leads the prayer) who recites another. A Muslim from Cairo, where Hafs is recited, and a Muslim from Casablanca, where Warsh is recited, can pray side by side without difficulty. The Qur'an says it was made easy to remember, and the readings are part of that ease.
The standard classical work on the readings. It lays down that a reading is accepted as Qur'an only if it fits the written form of one of Uthman's copies, is sound Arabic, and has a sound chain of transmission back to the Prophet (ﷺ). It notes that the seven readers chosen by Ibn Mujahid are not the same thing as the seven ahruf of the hadith, and that the readings which meet these conditions are all accepted as Qur'an.
“And We have indeed made the Qur'an easy to understand and remember: then is there any that will receive admonition?”
What critics say, and the answers
Sahih al-Bukhari 4992 — Kitab Fada'il al-Qur'an (Virtues of the Qur'an), hadith 4992
Umar heard Hisham ibn Hakim recite Surat al-Furqan differently from the way he had learned it and brought him to the Prophet (ﷺ). The Prophet had each recite, said of both readings that the surah was revealed that way, and said the Qur'an was revealed to be recited in seven ways, so recite whichever is easier.
Cited for
Umar and Hisham ibn Hakim, two companions, recited the same chapter differently, so from the start there was no single Qur'an.
The response
Both men had learned their recitation from the Prophet (ﷺ) himself, and he confirmed both as revealed. The difference was not a corruption found later. It was taught by the Prophet (ﷺ), from revelation. Both recitations were the same chapter with the same content.
Where it lands — Variation that the Prophet (ﷺ) himself taught is part of the revelation, not a change to it.
Qur'an 1:4 — Surat al-Fatiha (The Opening), verse 4
“Master of the Day of Judgment.”
Cited for
Hafs reads "Master" and Warsh reads "King", so the Qur'an's words have been changed.
The response
Both readings are one written word in Uthman's copies. Both have been recited with unbroken chains back to the Prophet (ﷺ). Master of the Day of Judgment and King of the Day of Judgment are both true of God (﷾), and neither contradicts the other. Most other differences are of the same kind or smaller: a vowel, a letter, or now and then a short word such as "and". In that case, the copies Uthman sent to different cities themselves differed by that letter. None contradicts another reading or changes a belief.
Where it lands — The readings are one Qur'an recited in approved ways. They are not different versions.
Perspectives
Christian critics
Some Christian apologists argue that printed Qur'ans in Hafs and Warsh differ, so Muslims cannot claim a single, unchanged text.
The Hafs and Warsh readings differ in a number of words, as well as in vowels and pronunciation.
Rebuttal
Islam agrees that a small number of words differ. A detailed comparison found that very few of these differences change the meaning. Where one does, both readings were revealed and neither contradicts the other, as "Master" and "King" are both true of God (﷾).
These differences show there are different Qur'ans, as there are different Bibles.
Rebuttal
These are not rival texts. Each accepted reading fits the written form of Uthman's copies, and none contradicts another. The Prophet (ﷺ) himself approved more than one mode, so a Muslim may pray behind an imam who recites either.
The Islamic perspective
The Prophet (ﷺ) taught the Qur'an in more than one mode, by revelation, as an ease for his people. The readings recited today all go back to him. Each fits the written form of one of Uthman's copies, and none contradicts another.
The Prophet (ﷺ) approved two different recitations of the same chapter and said the Qur'an was revealed in seven modes.
The Prophet (ﷺ) kept asking for the Qur'an to be recited in more modes, and was given seven. He told his companions to recite in whichever was easier.
Nearly all differences between Hafs and Warsh are in vowels and letter-dots, and very few affect the meaning.
A reading is accepted as Qur'an only if it meets three tests. It fits the written form of one of Uthman's copies. It is sound Arabic. It has a sound chain of reciters back to the Prophet (ﷺ).