I can see that ZMQ have done some work on this: https://github.com/zeromq/php-zmq/pull/212, but whether or not that is in your distribution is beyond what I can help you with 
you would be better off asking on a forum dedicated to ZMQ or the distro you’re using.
Our latest release uses Alpine 3.12 which is still PHP 7.3, so perhaps that is the best option for now.