Schubert: Ständchen 'Zögernd leise', D920 (D921)

Schubert wrote two versions of Ständchen “Zögernd leise”, for male and female chorus, originally catalogued as:
D 920, for alto solo, TTBB chorus & piano
D 921, for alto solo, SSAA chorus & piano, Op. 135

The latest update of Deutsch’s catalogue places both versions under D 920, and D 921 is no longer used.