Hello Abtaf,
I was looking about Moove's version and I found Moove don't version in Moodle 3.6, only Moodle 3.5.
In Moodle 3.6, the messaging changed and It's using a new system. Now the new messaging system appears in the right side, when you push messaging's icon.
Look here:
https://docs.moodle.org/dev/Moodle_3.6_release_notes
https://tracker.moodle.org/browse/MDL-63303
