Hi, i had the same annoying problem I did the following
Add the following to your functions.php file in your themes folder.
function remove_dashboard_donate_message() {
?>
<style>
div[id^="donation-to-dennis-hoppe-"]{
display: none;
</style>
<?php
}
add_action( 'admin_head', 'remove_dashboard_donate_message' );
Consequently, you could also add it as a style, in the plugin’s css file- add the following lines
div[id^="donation-to-dennis-hoppe-"]{
display: none; }
Hope this helps.