trying to upgrade from v1.15.2 to v1.18 i get a bunch of errors when trying to access. The php version was changed to 8.1.
This are the errors:
Deprecated: Optional parameter $namespace declared before required parameter $key is implicitly treated as a required parameter in /home/todomi5/public_html/tm/osticket/include/class.config.php on line 198

Deprecated: Return type of BaseList::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.util.php on line 101

Deprecated: Return type of BaseList::count($mode = COUNT_NORMAL) should either be compatible with Countable::count(): int, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.util.php on line 106

Deprecated: Return type of ListObject::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.util.php on line 220

Deprecated: Return type of ListObject::offsetGet($offset) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.util.php on line 198

Deprecated: Return type of ListObject::offsetSet($offset, $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 /home/todomi5/public_html/tm/osticket/include/class.util.php on line 207

Deprecated: Return type of ListObject::offsetUnset($offset) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.util.php on line 227

Deprecated: Return type of ModelMeta::offsetExists($field) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 242

Deprecated: Return type of ModelMeta::offsetGet($field) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 236

Deprecated: Return type of ModelMeta::offsetSet($field, $what) 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 /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 239

Deprecated: Return type of ModelMeta::offsetUnset($field) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 245

Deprecated: Return type of QuerySet::getIterator($iterator = false) should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1565

Deprecated: Return type of QuerySet::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1596

Deprecated: Return type of QuerySet::offsetGet($offset) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1599

Deprecated: Return type of QuerySet::offsetSet($a, $b) 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 /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1605

Deprecated: Return type of QuerySet::offsetUnset($a) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1602

Deprecated: Return type of QuerySet::count() should either be compatible with Countable::count(): int, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1371

Deprecated: Return type of CachedResultSet::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1743

Deprecated: Return type of CachedResultSet::offsetGet($offset) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1747

Deprecated: Return type of CachedResultSet::offsetSet($a, $b) 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 /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1754

Deprecated: Return type of CachedResultSet::offsetUnset($a) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 1751

Deprecated: Return type of ModelInstanceManager::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2002

Deprecated: Return type of CallbackSimpleIterator::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2046

Deprecated: Return type of CallbackSimpleIterator::next() should either be compatible with Iterator::next(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2051

Deprecated: Return type of CallbackSimpleIterator::key() should either be compatible with Iterator::key(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2036

Deprecated: Return type of CallbackSimpleIterator::valid() should either be compatible with Iterator::valid(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2040

Deprecated: Return type of CallbackSimpleIterator::rewind() should either be compatible with Iterator::rewind(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2031

Deprecated: Return type of FlatArrayIterator::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2076

Deprecated: Return type of HashArrayIterator::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.orm.php on line 2099

Deprecated: Return type of BaseMessageStorage::getIterator() should either be compatible with IteratorAggregate::getIterator(): Traversable, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /home/todomi5/public_html/tm/osticket/include/class.message.php on line 186

Warning: ini_set(): Session ini settings cannot be changed after headers have already been sent in /home/todomi5/public_html/tm/osticket/bootstrap.php on line 19

Warning: session_cache_limiter(): Session cache limiter cannot be changed after headers have already been sent in /home/todomi5/public_html/tm/osticket/bootstrap.php on line 21