Newman

This plugin allows you to hide plugin update notifications for wordpress plugins that you do not want to update. 
 Once this plugin is installed and activated, a link will appear under each plugin with available updates that will allow you to block notifications for that update. Once hidden, a link will appear allowing you to unhide the notifications.
This plugin uses WordPress hooks and filters to hide the notifications.

Plugin Update Hider

This plugin allows you to hide plugin update notifications for wordpress plugins that you do…

Plugin Update Hider vs UpStream: a Project Management Plugin for WordPress