MirrorMirror.onMessage is not a function

[Criviere]

TypeError: MirrorMirror.onMessage is not a function
at Class.alexa_start (/home/pi/MyMirror/MagicMirror/modules/MMM-MirrorMirrorOnTheWall/node_helper.js:15:18)
at Class.socketNotificationReceived (/home/pi/MyMirror/MagicMirror/modules/MMM-MirrorMirrorOnTheWall/node_helper.js:35:12)
at Socket. (/home/pi/MyMirror/MagicMirror/modules/node_modules/node_helper/index.js:113:11)
at emitTwo (events.js:126:13)
at Socket.emit (events.js:214:7)
at /home/pi/MyMirror/MagicMirror/node_modules/socket.io/lib/socket.js:513:12
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickCallback (internal/process/next_tick.js:180:9)

• Hello, I'm trying to fix this issue... any help is appreciated, thanks!