Prepare PHP new functionalities to current system

Clients upload invoice files (xlsx format) to the platform. Currently, the xlsx has no expiration date field. When a file is uploaded, the system automatically assigns the 10th of the current month as the default expiration date. We need to support an optional expiration date column in the xlsx, and display it correctly in the UI. It should be optional because not all invoices include an expiration date, only specific ones. Nowadays we receive this invoices from emails with domain a and b to the email c , and we have a CRON that runs twice, once to upload those files, and the second time ro read them.