Requirements
Version 1.2.0 requires WordPress 6.0+, PHP 7.4+ and active WooCommerce. The readme specifies WooCommerce 8.0 as the minimum. Both classic orders and HPOS are supported.
Install from WordPress.org
- Install and activate WooCommerce.
- Open Plugins → Add New and search for Inference Works Order Invoice Attach for WooCommerce. Alternatively, download the ZIP from WordPress.org and choose Upload Plugin.
- Install and activate it. The plugin is Free only; no purchase or license key is required.
- Open Inference Works → Order invoices and choose which emails receive the PDF.
- On the order edit screen, find the Invoice PDF metabox and upload the finished invoice. Then change the status or send the customer invoice email.
The plugin does not issue documents: prepare the PDF in your accounting software. It does not assign numbers, use accounting APIs or create credit notes.
Upgrade from 1.1.0 or earlier
Version 1.2.0 uses the new slug inference-works-order-invoice-attach. Deactivate the former plugin before activating this version. Do not delete the old plugin with invoice cleanup on uninstall enabled. Existing settings are imported without overwriting new settings; legacy metadata and download links remain readable. PDFs are not moved. If both copies are active, the new version suspends its internal handling until the old one is deactivated, avoiding duplicate hooks.
File access
New invoices are stored in wp-content/uploads/iwoia-invoices/{year}/{month}/ under random 32-character filenames, outside the media library. Older invoices may remain in oia-invoices.
On Apache the plugin writes additional index.php and .htaccess protection. Nginx ignores .htaccess: your server administrator must deny direct public access to both invoice directories. Random names make URLs harder to guess but do not replace access control. The download endpoint checks permissions for shop managers, the order owner or a valid guest order key.