German infantryman in late-war uniform

Rui’s Renditions
An anonymous German infantryman in late-war uniform. Possibly late 1917-1918.
Of note are his trousers which, in my opinion, were made of feldgrau instead of grey cloth. Due to a shortage of grey cloth, from 14 November 1917, feldgrau started being used (1).
According to the owner of the original, this photo was bought together with others that were sent to relatives in north Slesvig (Schleswig), in what is today Denmark. Unfortunately, nothing is written on this one so there’s no way of knowing if he was of Dane descent.
Original property of Ole Achilles, with his kind permission.
(1) “The German Army in World War I (3)”; Thomas, Nigel (2004); Osprey Publishing