On Thursday, 22 December 2016 21:38:49 UTC-7, Eric Bick (ZN7) wrote:
Preliminary notification of publication scheduled for December 23.

https://www.federalregister.gov/docu...ers-withdrawal

Thanks for posting this Eric. For those who have not or do not have the time to slog through this document, this to me is the most relevant part of the document

Conclusion
When further testing, research, and conclusive data is available that reflect alternative mitigations, a broader, more harmonized proposal may better serve the public interest. Withdrawal of Notice No. 15-05 does not preclude the FAA from issuing another notice on the subject matter in the future or committing the agency to any future course of action. The agency will make any necessary changes to the regulations through a notice of proposed rulemaking (NPRM) with the opportunity for public comment.

Although the FAA has determined that a regulatory course of action is not warranted at this time, the FAA will continue to work with local glider communities, encourage the voluntary equipage of transponders in gliders and encourage the use of TABS. The FAA continues to recommend that all glider aircraft owners equip their gliders with a transponder meeting the requirements of § 91.215(a), a rule-compliant ADS-B Out system, or a TABS device. In consideration of the above factors, the FAA withdraws Notice No.. 15-05, published in 80 FR 34346, on June 16, 2015.