When I email myself a .zip containing the SDK8-type DFU payload, I can no longer "long press" on the email attachment and have it opened in nRF Toolbox. Either the jackballs at Apple screwed this up or somehow iOS 9 "de-registered" the Nordic app as one possible handler of .zip files. I deleted and reinstalled nRF Toolbox from the App Store, but that didn't help.
Thank you Nordic engineers for giving us a workaround using iTunes to drop .zip files into the Toolbox app. (I will not abstain from saying that using iTunes to accomplish this, on a Windows machine, is like pouring battery acid into your eyes. Again, thanks to the dumb Apple software guys.)
Dan