In January 2016, the Gypsum Association (GA) released GA-216-2016, Application and Finishing of Gypsum Panel Products. On page 3, section 2.2.12.4 should read:

2.2.12.4 Where studs complying with ASTM C645 are used to receive Abuse Resistant or Impact Resistant Gypsum panels, they shall be not less than 0.0312 in. (0.792 mm) design thickness and shall be in accordance with sections 4.3 and 8.1 of Specification C645.

The correction clarifies the recommended thickness for steel studs receiving abuse resistant or impact resistant gypsum panels contained in GA-216-2016. The GA is communicating this errata as widely as possible. The electronic version of GA-216-2016 currently reflects this change and hardcopies of Application and Finishing of Gypsum Panel Products are now issued with the clarification noted as an errata inserted on a separate sheet. 

The errata, itself, is available as a free download on the GA website.