joe134cd:
As far as I am aware (and I have only stopped going a few months ago) there has never been any revised or completely new addition to the "should you believe in the trinity" brochure.
Both the linked PDF provided in this thread and the version on the Watchtower Library on CD-ROM state that it is the "2006 printing". The newer printing has the following differences to the original 1989 printing (as provided in the 2004 Watchtower Library).
Page 7: The newer version deletes a claim that Clement of Alexandria "called Jesus in his prehuman existence “a creature”"
The following mundane changes are also made to the digital version that do not affect the printed editions:
- The older version doesn't include the 'Title page', 'Publishers' page' or 'Foreword' in the CD's chapter index
- The initial questions have been moved from the first chapter to the 'Foreword'
- The note about the NWT is moved from the first chapter to the 'Publishers' page'
- In the old version, spaces between words formatted as bold or italic are not similarly formatted.
- Some spaces (mainly within scripture references) have been changed to non-breaking spaces.
- Some hyphens have been changed to non-breaking hyphens.
- Accent marks in Hebrew transliterations have been replaced with visually similar characters that do not alter the meaning.
- Some Greek characters with diacritics have been replaced with similar characters that do not alter the meaning.