@tyrannous But that uses untrailingslashit and that uses rtrim and wouldn’t get rid of the issue.
@rgwpladapa 8.0 is supported. I don’t think that is the issue right now.
In general: When I run WordPress 6.0.2 on a local WAMP stack with PHP 8.1.6 I still receive lots of deprecation notices that generate from WordPress core e.g.
PHP Deprecated: rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in ..\wp-includes\formatting.php on line 2772
PHP Deprecated: Return type of Requests_Cookie_Jar::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in ..\wp-includes\Requests\Cookie\Jar.php on line 63
PHP Deprecated: Return type of Requests_Utility_CaseInsensitiveDictionary::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in ..\wp-includes\Requests\Utility\CaseInsensitiveDictionary.php on line 40
PHP Deprecated: http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated in ..\wp-includes\Requests\Transport\cURL.php on line 345
And that is when I have no plugins whatsoever enabled. So I am not sure whether this is meant with “technically supported”.