[Plugin: Affiliate Hoover] Error

getting an error message on plugin versions .88 upwards to the latest version .95 error reads
“Access to undeclared static property: OptionModelSub\Form_Model_Alpha::$max_upload in /home/content/36/9055236/html/wp-content/plugins/affiliate-hoover/model/Form_Model_Alpha.php on line 657”

occurs when we try upload feed either csv or url

https://www.ads-software.com/extend/plugins/affiliate-hoover/