Sakthivel S

This plugin is used disable the wordpress functionality of updating core, themes & plugins automatically. Also it will disable all kind of update notification from wordpress.org theme/plugin repository.
Features 
* Disable WordPress core, themes, plugin update 
* Disable notifications for all updates available.

Disable All Updates & Notifications

Disable Wordpress, Themes & Plugins Updates along with their update notifications.

Belo

The Hide Admin Dashboard Notifications plugin enables you to disable dashboard notifications for specific or all admin users. This enables admin users to focus on more important tasks on the system which boosts productivity.

Hide Admin Dashboard Notifications

Disable unnecessary dashboard notifications for admin users and boost productivity.

Disable All Updates & Notifications vs Hide Admin Dashboard Notifications