The sonata is absent from later lists of his compositions, and its fate is unknown. The opus number was taken over by (likewise rather mysterious) Little Pieces for piano, possibly the same miniatures that Koffler mentioned in a letter to Alois Hába of 7 April 1936:
Let me take the liberty to dedicate these “simple” piano pieces to your daughter, though I’m afraid you may not like them.
The work may have been related in some way to Little Pieces for Children, marked as Op. 16a in Koffler’s own inventory of ca 1935, and to Little Serenade (Divertimento) for reed trio.