iTunes 12.7 Pulled?
When Apple released macOS High Sierra 10.13 beta 3 to developers on July 10 a download for iTunes 12.7 (build 12.7.0.48) was also made available. By July 17, when I installed the Beta for the first time on another machine, iTunes 12.7 was no longer available for download.
There were reports on the Developer Forum about devices not being recognized so perhaps this is part of the reason for pulling it.