The Nieuport 23C-1 replica built by Nieuport Memorial Flyers made a successful maiden flight in Grenchen, Switzerland, on 21 September 2020. The aircraft, registered HB-RNA, was flown by Isidor von Arx. It is powered by the rotary engine of a Thulin A (Swedish license-built Blériot XI).
This project was started in the year 2000. Its progress can be followed on the Nieuport Memorial Flyers website. The website is in German but you can access an automatically-translated version of it here.
Congratulation to the Nieuport Memorial Flyers team for this superb work, and h/t to Sébastien for the information.