WooCommerce PDF Invoice is the most professional and feature-rich invoicing extension which comes with premium support. For those that mean business.
Invoicing extensions are not ordinary extensions – documents must comply with accounting standards and regulations, the extension itself must be very reliable as a single flaw can mean additional costs later on.
[+] Added an option to trigger Customer Invoice emails for all new orders
[*] Fixed a bug related to tax in additional order fees
[*] Replaced constants MAX_FIRST_PAGE_HEIGHT and MAX_PAGE_HEIGHT with properties
[*] Improved compatibility with WooCommerce 2.3
[*] Improved internal invoice numbering sequence algorithm to avoid duplicates