Emails also sent when post is updated, not just when it?s published

Mine also does this and I agree that it is not ideal.

I have fixed this the following way:

go in st-category-email-subscribe.php in the Plugin Directory.

around Line 250 you should find this:

add_action('publish_post','st_send_email');

=> This triggers the Send Email funktion. Comment this out and add this below:

function on_all_status_transitions( $new_status, $old_status, $post ) {
    if ( $old_status != 'publish' ) {
		add_action('publish_post','st_send_email');
    }
}
add_action(  'transition_post_status',  'on_all_status_transitions', 10, 3 );

Works for me