Hi,
currently you need to take a copy of all your custom files (for pdf, css, lang) and invoice templates in all kind of subdirectories when moving to a new version.
It would be nice if those customizations could be moved outside the source distribution directories (for languages a certain tree would be needed of course) and in ipconfig.php a setting would point to the separate dir containing all customizations.
Btw, the instructions at https://wiki.invoiceplane.com/en/1.5/getting-started/updating-ip don’t mention the backup needed for custom_lang.php .
Franky