The DICOM Editor, David Clunie informs that the 2015b release of the DICOM standard is now available from the NEMA ftp site:
It is also indexed from the DICOM Editor's status page at:
This replaces the 2015a release.
Release notes are at:
The changes from the 2015a release are shown highlighted in PDF files; note that changes to figures are not detected and some changed figures are not rendered in the diff files: