Fehlermeldung

• Deprecated function: Return type of Drupal\bootstrap\Utility\Storage::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 28 of themes/bootstrap/src/Utility/Storage.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\Storage::next() should either be compatible with Iterator::next(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 28 of themes/bootstrap/src/Utility/Storage.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\Storage::key() should either be compatible with Iterator::key(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 28 of themes/bootstrap/src/Utility/Storage.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\Storage::valid() should either be compatible with Iterator::valid(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 28 of themes/bootstrap/src/Utility/Storage.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\Storage::rewind() should either be compatible with Iterator::rewind(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 28 of themes/bootstrap/src/Utility/Storage.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\StorageItem::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 20 of themes/bootstrap/src/Utility/StorageItem.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\StorageItem::next() should either be compatible with Iterator::next(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 20 of themes/bootstrap/src/Utility/StorageItem.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\StorageItem::key() should either be compatible with Iterator::key(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 20 of themes/bootstrap/src/Utility/StorageItem.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\StorageItem::valid() should either be compatible with Iterator::valid(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 20 of themes/bootstrap/src/Utility/StorageItem.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\StorageItem::rewind() should either be compatible with Iterator::rewind(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 20 of themes/bootstrap/src/Utility/StorageItem.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\ArrayObject::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 17 of themes/bootstrap/src/Utility/ArrayObject.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\ArrayObject::offsetExists($key) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 17 of themes/bootstrap/src/Utility/ArrayObject.php).
• Deprecated function: Return type of & Drupal\bootstrap\Utility\ArrayObject::offsetGet($key, $default = null) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 17 of themes/bootstrap/src/Utility/ArrayObject.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\ArrayObject::offsetSet($key, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 17 of themes/bootstrap/src/Utility/ArrayObject.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\ArrayObject::offsetUnset($key) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 17 of themes/bootstrap/src/Utility/ArrayObject.php).
• Deprecated function: Drupal\bootstrap\Utility\ArrayObject implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in include() (line 17 of themes/bootstrap/src/Utility/ArrayObject.php).
• Deprecated function: Return type of Drupal\bootstrap\Utility\ArrayObject::count() should either be compatible with Countable::count(): int, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in include() (line 17 of themes/bootstrap/src/Utility/ArrayObject.php).
• Deprecated function: Drupal\bootstrap\Utility\DrupalAttributes implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in include() (line 16 of themes/bootstrap/src/Utility/DrupalAttributes.php).
• Deprecated function: Drupal\bootstrap\Utility\Variables implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in include() (line 10 of themes/bootstrap/src/Utility/Variables.php).
• Deprecated function: Drupal\bootstrap\Utility\Element implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in include() (line 571 of vendor/composer/ClassLoader.php).
• Deprecated function: Drupal\bootstrap\Utility\Attributes implements the Serializable interface, which is deprecated. Implement __serialize() and __unserialize() instead (or in addition, if support for old PHP versions is necessary) in include() (line 571 of vendor/composer/ClassLoader.php).