I guess we need doctrine/persistence#437 first

for some of the __sleep()/__wakeup() related deprecations an update of symfony/string would be required but we only introduced the new methods in the upcoming 7.4 release

https://wiki.php.net/rfc/soft-deprecate-sleep-wakeup which looks to be accepted in a few days looks promising here and the merge of php/php-src#19966 will then unlock the ability to actually get the job green here

We don't need to worry about the __sleep()/__wakeup() deprecations for now as the aforementioned RFC passed. However, before being ready for PHP 8.5 in ORM we also need DBAL to be compatible (see doctrine/dbal#7173 and doctrine/dbal#7174).