Marei worked on the kivitendo/kivitendo-erp repository, focusing on improving the accuracy of financial document templates. They delivered a targeted bug fix that corrected the rendering of department fields by updating template logic to reference billing_address_department_2 instead of department_2, ensuring the second department appears only when present. This change was applied across multiple document types, including invoices, credit notes, proformas, statements, and payment reminders. Using LaTeX and TeX, Marei enhanced template development and modification processes, resulting in more consistent and reliable customer-facing documents. The work addressed a nuanced issue, reducing confusion and potential support requests in billing workflows.