Bunch of errors wordpress-6.0-beta2.zip with PHP 8.1.5

[campation]

on my development site (Plesk Obsidian, Centos 7.9) a fresh installed latest WP 6.0 beta2 does create a lot of errors when switching from PHP 8.0.18 (error free) to PHP 8.1.5.

See attached debug.log created during first login as admin.

Chris
PS: no answer required

[21-Apr-2022 10:59:44 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 63
[21-Apr-2022 10:59:44 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetGet($key) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 73
[21-Apr-2022 10:59:44 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetSet($key, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 89
[21-Apr-2022 10:59:44 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 102
[21-Apr-2022 10:59:44 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 111
[21-Apr-2022 10:59:44 UTC] PHP Deprecated:  http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Transport/cURL.php on line 345
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 40
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetGet($key) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 51
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetSet($key, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 68
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 82
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 91
[21-Apr-2022 10:59:45 UTC] PHP Warning:  Cannot modify header information - headers already sent by (output started at /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php:15) in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-admin/admin-header.php on line 9
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  setcookie(): Passing null to parameter #5 ($domain) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/option.php on line 1111
[21-Apr-2022 10:59:45 UTC] PHP Warning:  Cannot modify header information - headers already sent by (output started at /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php:15) in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/option.php on line 1111
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  setcookie(): Passing null to parameter #5 ($domain) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/option.php on line 1112
[21-Apr-2022 10:59:45 UTC] PHP Warning:  Cannot modify header information - headers already sent by (output started at /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php:15) in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/option.php on line 1112
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:45 UTC] PHP Deprecated:  rtrim(): Passing null to parameter #1 ($string) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/formatting.php on line 2772
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 63
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetGet($key) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 73
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetSet($key, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 89
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 102
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 111
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  http_build_query(): Passing null to parameter #2 ($numeric_prefix) of type string is deprecated in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Transport/cURL.php on line 530
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 63
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetGet($key) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 73
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetSet($key, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 89
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 102
[21-Apr-2022 10:59:46 UTC] PHP Deprecated:  Return type of Requests_Cookie_Jar::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Cookie/Jar.php on line 111
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 40
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetGet($key) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 51
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetSet($key, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 68
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 82
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 91
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 40
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetGet($key) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 51
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetSet($key, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 68
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 82
[21-Apr-2022 10:59:47 UTC] PHP Deprecated:  Return type of Requests_Utility_CaseInsensitiveDictionary::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/vhosts/campation.com/subdomains/beta/httpdocs/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 91

[costdev]

Hi @campation, thanks for opening this ticket!

Deprecation notices are not errors and are nothing to be concerned about. Everything will still work as it should when WP_DEBUG is turned off (as it should be on production websites).

Also see this blogpost: ​https://make.wordpress.org/core/2022/01/10/wordpress-5-9-and-php-8-0-8-1/

The update of the Requests library is already being tracked in #54504, so I'll close this issue as a duplicate.