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Follow their blogs here. As of Feb. 2018 they are off to a great start in sharing their Grouper journey:
Maslow's Hammer
https://spaces.at.internet2.edu/x/qQYmBw
Groveling before Grouper
https://spaces.at.internet2.edu/x/_IVQBw
In addition, University of Michigan presented on their Grouper deployment at the Feb. 14, 2018 IAM Online webinar. See the slides: https://www.incommon.org/docs/iamonline/20180214_IAMOnline.pdf and recorded webinar: http://internet2.adobeconnect.com/p03kw4etow2t/
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