Download of PDiff 1.1 for Mac was available from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software lies within Design & Photo Tools, more precisely Presentation Tools. This Mac application is a product of CSci Computer Science. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
What exactly has changed, what is really the same? How often do you get back a document and are still uncertain about the changes? Why is it such a hard task to juggle with revisions edited by many authors? If you just want to *see* what happened, then PDiff is made for you! PDiff allows you to compare the content of two PDFs in order to pinpoint all textual changes.
You may want to check out more software for Mac, such as PDiff Express 2, which might be similar to PDiff.