In the preface to his XII. Sonates à un Hautbois de Concert, which were published in Amsterdam (possibly in around 1710), Muller (also known as Johann-Michael) describes himself as "Director of Music and Organist" at the court of Philippe Reinhard of Hanau, who died in 1712. The pieces are written in such a way that they can be performed by solo oboe with an accompanying ensemble of either winds (two oboes, taille and bassoon) or strings (two violins, viola, cello) with Basso continuo.
A complete recording, featuring Marianne Richert-Pfau, the editor of these editions, can be found (and purchased) here.