If you are receiving update notifications for YaBB (Yet another Bulletin Board) even after it had been uninstalled, please check if following file exist under your cpanel account.

/home/username/.cpaddons/cPanel::Bulletin_Boards::YaBB.0.yaml

If the file is there, then simply remove it or rename it. The email address to which notifications are sent is mentioned in the above file. You should not receive any notifications emails after removing the file.