Isomorphisms of unitary forms of Kac–Moody groups over finite fields

We use the methods developed in [Pierre-Emmanuel Caprace, “Abstract” homomorphisms of split Kac–Moody groups, Mem. Amer. Math. Soc. 198 (2009); Pierre-Emmanuel Caprace, Bernhard Mühlherr, Isomorphisms of Kac–Moody groups, Invent. Math. 161 (2005) 361–388; Pierre-Emmanuel Caprace, Bernhard Mühlherr, Isomorphisms of Kac–Moody groups which preserve bounded subgroups, Adv. Math. 206 (2006) 250–278] to solve the isomorphism problem of unitary forms of infinite split Kac–Moody groups over finite fields of square order.