Errors in php application after update linux server.

After an update of our client’s Linux server, the php application running alongside his website is throwing all kind of errors. This application was not developed by us but by another company that does not exist anymore. The application gets records from the database and displays them in a table. This table has a variety of filters and sort options. There’s also the possibility to export the table data to a csv file. It’s still possible to get the records from the database and apply some filters but with a lot of errors showing in the table, of which most are “Undefined index”. (see screenshot for some example errors) Because this application is an indispensable element of our client’s business, the errors should be fixed asap. GOAL: - Test all existing filter/sort combination & export functionality for errors - Fix all errors Include in your offer: - Relevant experience