4.511 is not valid number for plugin updater: So you simply need to change that to something lower (e.g. 4.5 or 4.4) just open plugin editor find hide-my-wp.php and change that number which is located at the top of the file.
Then go to Dashboard > Update > Check to see new version!
Also you can opt for manual update.
– first goto HMWP > Start tab and do “Export current settings” – save it somewhere.
– download latest HMWP version, and delete hide_my_wp plugin folder from /wp-content/plugins/ directory.
– using FTP/cpanel upload latest hide_my_wp plugin folder to /wp-content/plugins/ directory.
– goto website backend and activate HMWP plugin.
– goto HMWP > Start tab and import settings (from previously saved settings)