When did Koine Greek stopped being used?

Question

When did Koine Greek stopped being used?

Answer 1

Like every other form of Greek language, Koine Greek didn't stop being used but developed in Medieval Greek, which is specifically proved by the Dymotika Tragoudia (Traditional Greek songs). The last phonological alteration in the 10th c.  was "iotakismos" (ιωτακισμός) both of the letters «οι» and  Ã‚«Ï…» which had been pronounced like the french "u" till

then.

♥Iotakismos=pronunciation of the greek letters (or combination of letters) "ει "οι", "υ", "η" like the greek letter iota "ι"( meaning like the letters "ee" in the word "tree")

Hope this helps!