Hey, I found library copies of the new editions of the “Official iBT Tests” books (Vol. 1, 3rd edition, Vol. 2, 2nd edition) to see what was new.
The text seems to be 100% the same, except for a couple of references to online materials in the introduction. The old editions already had the reordered listening questions from the Official Guide (4th edition) and the varied Integrated writing prompts from the Official Guide (3rd Edition). Those are continued here, of course.
The “Tests” books do NOT contain the longer independent writing prompts (with the warning about memorized examples) found in the Official Guide (4th Edition).
The only difference I can see is that the tests are now delivered on DVD, rather than CD. I didn’t examine every page, though, so let me know if there is something I can double check for you.
For the record, these are 2019 publications. However, they will be somewhat obsolete when the TOEFL changes in August 1 of 2019. When that happens ETS will include an “insert” in future printings of their books that describe the new version of the test. This does not mean they will update them! The insert will just be a piece of paper that describes the changes. ETS does not know when the actual text of the books will be updated.
Update from 2020: ETS has hinted that new editions of some of their books will be published this year, but nothing has been made official.