In Plugin update version 3.13.5 we have started preparing for PHP 8.
However, there are still some known depreciation notices that we are working on resolving:
"WordPress is not fully compatible with PHP 8.0 or 8.1. All remaining known PHP 8.1 issues are deprecation notices. Please note, a deprecation notice is not an error, but rather an indicator of where additional work is needed for compatibility before PHP 9 (i.e. when the notices become fatal errors). With a deprecation notice, the PHP code will continue to work and nothing is broken."
More information can be found here: https://make.wordpress.org/core/2022/01/10/wordpress-5-9-and-php-8-0-8-1/