It's been added to both updates through Software Update, and the App Store download has been updated to include it too. The standalone updates will likely be repackaged soon if they haven't already.
The Supplemental now has some weird screen trash, a pattern of small rectangles as it boots to the desktop screen. It didn't do that until this latest update.
After installing the supplemental, iStat menus on my rMBP has an issue.Disk space is wrong. It shows nothing used and 1.46TB available. I wish! About this Mac also reports storage wrong. It reports 223.9GB available which is about right but the graphic shows the entire disk being used by Backup(140.74TB)