But unfortunately I can not find a line with the upgrade
Open the file "admin/applications/forums/sources/classes/forums/class_forums.php"
Find:
'select' => 'm.members_display_name, m.members_seo_name',
so looks like line 2048
'select' => 'm.members_display_name, m.members_seo_name,m.member_group_id',