Warning on email-post page

Using: Email Posts to Subscribers 5.4.1; WordPress 5.3.2 Multisite

On: wp-admin/admin.php?page=email-post

Get :
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘elp_admin_option’ not found or invalid function name in [site]/wp-includes/class-wp-hook.php on line 288

Looks like previous support post from over 2 yrs ago here:

https://www.ads-software.com/support/topic/error-on-email-post-page-redux/

which reports it was a bug

Thanks in advance for help