Still under dispute as far as I can tell. Evidently, a group of ambassadors from Gambia have issued a letter calling for Jammeh to accept his loss. (
http://www.freedomnewspaper.com/gambia-breaking-news-gambian-diplomats-call-on-jammeh-to-step-down/)
Guardian says that African leaders are also calling for him to step aside, and will attend the innaugaration of the new leader (
https://www.theguardian.com/world/2016/dec/18/african-leaders-back-adama-barrow-as-new-president-of-the-gambia). Pressure seems to be building on Jammeh from many sources.