What’s a new edition? What’s a reprint?
What constitutes a book that’s been updated, revised, or expanded into a new edition? Enough of a change to the contents so that it's not quite the same book. Typically, this means significant rewriting and/or restructuring, new material added, outdated material removed, and so on. The book will feature a new preface, if it has one; and if there's a foreword, a new foreword as well. Each in its own way will situate this new and changed edition with respect to the previously published version. The book will also carry a new ISBN.
A book reissued with no changes, or only minor copyediting fixes, is a reprint. A book reissued with a new cover or other repackaging is a reprint.
Updated, revised, or expanded editions are typical of informational nonfiction. Works of fiction and narrative nonfiction are not typically revised and updated, except under special circumstances such as the release of a new critical edition or translation.