These questions were answered in the scope of 7.0.x and 7.1.x versions. However, if you find links to our GitHub repo, then they should target the latest version, and you can get access to specific versions by using the Tags functionality.
Since 2013, StackOverflow is the most important channel used by iText Software to answer questions about iText from developers who do not have access to Premium support. Many of these questions are answered by iText's original developer, Bruno Lowagie. Once Bruno noticed that he had answered more than 1,000 questions (resulting in a 20K+ reputation), he decided to bundle the most frequently asked, most useful and most interesting questions into a book.
The result is a book with answers to questions about PDF in general, high-level iText objects, low-level functionality, fonts, forms, page events, tables, HTML, and much more. If you have a question about iText, check out this book. If the question has been asked before, you may find the answer in this book.