Dismiss “Core Update” nag on dashboard, “Indicators” on admin menu and admin tool bar, “Maintenance Mode”, when is activated, or automatically, if it is in mu-plugins directory. Tips A neat trick, is to put this single file dismiss-update-nag.php (not its parent directory) in the /wp-content/mu-plugins/ directory (create it if not exists) so you won’t even have to enable it, and will be loaded by default, also, since first step installation of WordPress setup! About it The code of this plugin, is not written with a php framework, but with a simple php editor, manually, compatible UTF-8 without BOM and Unix LF.