35mm
Question: Will the book be updated with the latest tips and tricks for latest Sonar versions periodically? And if so can we just redownload the latest version without re-purchasing?
Frankly, I haven't thought that far ahead! Meanwhile, you can think of "Friday's Tip of the Week" as updates to the book.
I do think it will be quite some time before there's a revised version. What it's worth will depend on what goes into it. If the book is a complete rewrite, I assume it would be sold as a new book. But if it's mostly a revision with additional new material, probably what would be fairest to all concerned is to offer a significant discount to people who own the existing book, and sell it at full price to first-time buyers.