I too am having the same issue
Notice: Undefined offset: 1 in /home/content/48/7276448/html/wp-admin/includes/upgrade.php on line 1986
when i disable the plugin it goes away, when i enable it again it shows.
i’m using Maps Marker Pro® v2.3.1 on WordPress 4.2.2
PHP Version : 5.4.19
MYSQL Version : 5.0.96-log
plugin still works, it’s just annoying and i’m worried it could lead to future issues
