My friend Dan Brubaker published a rather remarkable book this past year, titled Corrections in Early Qur'ān Manuscripts (Think and Tell Press, 2019). One reviewer has noted that the book is the first of its kind. After briefly introducing the difficult and complicated subject of early Quran manuscripts, Dan sets out twenty examples of corrections from among the hundreds that he has personally found in ancient Quran manuscripts kept in libraries and museums around the world. For each correction, Dan gives a color photograph of the passage in the actual manuscript he is discussing. He observes whatever he reasonably can about the manuscript and the Quran passage in view, explains the nature of the correction, then shows what the correction means in terms of the "1924 Quran" text that most Muslims use today.
Dan's study leaves little doubt that corrections were made in early Quran manuscripts, but the analysis of what these corrections signify is another matter entirely. Here's where what would appear to many as egg-headed irrelevant details becomes a point of lively controversy for thousands. Just this week I have seen the first review of Corrections in the journal Al-'Usur al-wusta and some reverberations from that review on Twitter. It will be interesting to see what comes out of the response to this book. I will try to update this subject when I learn more.