Fix compatibility issue (parsing XML data) when upgrading from PHP 7.0 to 7.4

The code I have was provided to me some years back and works perfectly up to version 7.0 When I upgrade the server it throws approx 6 errors all similar to the example provided: "Fatal error: Uncaught Error: Cannot use string offset as an array in /var/www/xxxxxx/[login to view URL](258) : eval()'d code:1 Stack trace: #0" Can you solve the following Typical error? I want to upgrade a server to PHP 7.4 but the above typical error appears when moving from version 7.0 to 7.1 onwards. Approx 6 errors exist similar to above and it happens when parsing data in an XML file. I want all errors fixed however I believe that it's the same issue that is causing them. Are you familiar with upgrading php and issues with the eval() function?