Leider habe ich genau das selbe Problem...
Wordpress und alle Plugins sind auf dem neusten Stand.
Ich habe vor der Umstellung sogar alle Plugins deaktiviert und auf ein Standart-Theme umgestellt. Weder auf PHP 8.0 noch auf 8.1 oder 8.2 funktioniert das Frontend. Ins Backend komme ich und bekomme dort auch immer folgendes angezeigt:
REST-API-Endpunkt:
https://xy.de/wp-json/wp/v2/types/post?context=edit
REST-API-Antwort: (500) Internal Server Error
Den Debug-Modus habe ich an, dort gibt mir das Log bei PHP 8.0 nichts aus - bei PHP 8.1 oder 8.2 steht folgendes drin:
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Cookie_Jar:
ffsetExists($key) should either be compatible with ArrayAccess:
ffsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Cookie/Jar.php on line 63
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Cookie_Jar:
ffsetGet($key) should either be compatible with ArrayAccess:
ffsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Cookie/Jar.php on line 73
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Cookie_Jar:
ffsetSet($key, $value) should either be compatible with ArrayAccess:
ffsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Cookie/Jar.php on line 89
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Cookie_Jar:
ffsetUnset($key) should either be compatible with ArrayAccess:
ffsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Cookie/Jar.php on line 102
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Cookie_Jar::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Cookie/Jar.php on line 111
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Utility_CaseInsensitiveDictionary:
ffsetExists($key) should either be compatible with ArrayAccess:
ffsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 40
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Utility_CaseInsensitiveDictionary:
ffsetGet($key) should either be compatible with ArrayAccess:
ffsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 51
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Utility_CaseInsensitiveDictionary:
ffsetSet($key, $value) should either be compatible with ArrayAccess:
ffsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 68
[12-Jan-2023 18:38:31 UTC] PHP Deprecated: Return type of Requests_Utility_CaseInsensitiveDictionary:
ffsetUnset($key) should either be compatible with ArrayAccess:
ffsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 82
[12-Jan-2023 18:38:31 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 /mnt/web224/e0/57/58227557/htdocs/WordPress_01/wp-includes/Requests/Utility/CaseInsensitiveDictionary.php on line 91