For the manuscript tradition, see:
http://pinakes.irht.cnrs.fr/notices/oeuvre/13375/
For the edition, see Bibliography.
Discussion
This text most probably dates from the 8th century, but there is at least a slight possibility of an earlier dating.
Bibliography
Text with English translation:
Stallman, C.J. (ed.), The Life of Saint Pankratios of Taormina: Greek text, English translation and commentary (Byzantina Australiensia 22; Leiden, 2018).