Thanks for the community for letting me know about these questions - and also for producing Openbadges, which I believe is a brilliant idea, which I hope will achieve even more momentum and find broad adoption.
What is sunsetting is the Persona authentication that allows Backpack holders to associate multiple email addresses to a Backpack for validating their badges (since email addresses are also the validation data for adding a badge to a backpack).
DigitalMe of UK is taking on the development of a replacement credential for Mozilla’s Persona sign-in, and expects to have an announcement by November, following Mozfest 2016. At that time, we will have a better understanding of the users’ experience with the Backpack and can help them prepare for any changes that might be required.
If you are interested in the community call from this summer, you can listen to the recording
Open Badges Community Call
https://archive.org/details/OpenBadgesCommunityCall20161307
or review the etherpad notes
http://etherpad.badgealliance.org/CC2016July13
Looks like we are in a wait-and-see for the next few weeks.
Robin Sitten