What do you mean?
There are various ‘arch-update-notifier’ things .. but maybe you mean the cachy-update (fork of arch-update)?
If so and in comparison to something like pacman -Syu .. pacman simply does not report orphans by default while some of those other utilities check for and prompt about them automatically.
To print your current orphans you can execute, ex;
pacman -Qdt
It may also be worth reiterating something from a related thread;