How to extend the popup, that would be when the player joined him to write "Hi" for 10 seconds, the code please \(*_*)/
https://forums.pocketmine.net/threads/how-to-use-schedules-in-a-plugin.4796/ Here is a tutorial on tasks.
and check this : http://forums.pocketmine.net/threads/i-got-a-question-about-the-scheduledelayedtask.7345/
It's Player::sendPopup($msg, $subtitle);, not $this. And if Player::sendPopup($msg, $subtitle); isn't working in 1.6, then that's a bug.