Instructions to fix errors
Deprecated: outlining_columns_html is deprecated since version WooCommerce PDF Invoices v2.8!
Hiện không có giải pháp thay thế. in /homet/wpincludes/functions.php on line 4783
Deprecated: get_columns_count is deprecated since version WooCommerce PDF Invoices v2.8! Hiện
không có giải pháp thay thế. in /homet/wpincludes/functions.php on line 4783
Deprecated: get_colspan is deprecated since version WooCommerce PDF Invoices v2.8! Hiện không
có giải pháp thay thế. in /homet/wpincludes/functions.php on line 4783

How to fix it:
You are using micro template which is deprecated. I can advise you to switch to minimal.
This error that is being printed on a pdf invoice.
Step by step:
Woocommerce >>> Invoices >>> Template >>> Select, change Micro to Minimal.
Save
Done.