Fix: Fix errors caused by the new security restrictions in XenForo 2.3.9
This version fixes an issue that could cause the site to stop functioning after upgrading to XenForo 2.3.9 or newer.
Ideally, you should install this update prior to updating XenForo. If you have already updated and your site is inaccessible, you can download the update and extract the zip file, then upload the new files to your site.
Alternatively, you can disable DB Shop, then update XenForo, then update DB Shop.