diff --git a/connector/mattermost/mattermost.go b/connector/mattermost/mattermost.go
index 7c776d8..81adbde 100644
--- a/connector/mattermost/mattermost.go
+++ b/connector/mattermost/mattermost.go
@@ -327,12 +327,12 @@ func (mm *Mattermost) handlePosted(msg *model.WebSocketEvent) error {
 	}
 	userId := UserID(fmt.Sprintf("%s@%s", user.Username, mm.server))
 
-	if lastdn, ok := mm.userdisplaynamemap[userId]; !ok || lastdn != user.Nickname {
-		log.Warnf("Update displayname %s %s", userId, user.Nickname)
+	userDisp := user.GetDisplayName(model.SHOW_NICKNAME_FULLNAME)
+	if lastdn, ok := mm.userdisplaynamemap[userId]; !ok || lastdn != userDisp {
 		mm.handler.UserInfoUpdated(userId, &UserInfo{
-			DisplayName: user.Nickname,
+			DisplayName: userDisp,
 		})
-		mm.userdisplaynamemap[userId] = user.Nickname
+		mm.userdisplaynamemap[userId] = userDisp
 	}
 
 	// Build message event