Mitchwah- You seem to have some inside info. I did not know there was a 15D update until I saw your post. I had bookmarked the server link where I got 15, waiting for it to change, and it never did. Seems to be another unconventional Ectaco practice. Besides not telling us what is IN the update- they keep posting them at different locations. This link still lists 15.
ftp://custftp:FQSswyvGQ20So@ftp.ectaco.com/