Reply by Authors. Issue 4 (11th October 2021) - Chakiryan, Nicholas H.; Dahmen, Aaron; Bandini, Marco; Pederzoli, Filippo; Marandino, Laura; Albersen, Maarten; Roussel, Eduard; Zhu, Yao; Ye, Ding-Wei; Ornellas, Antonio A.; Catanzaro, Mario; Hakenberg, Oliver W.; et al.