Using alt-php56 in WHM

I am in the process of migrating an account from WHM under CentOS 7.9 to a new server running WHM under Ubuntu 20.04.4 LTS (both are running 104.0.7). There are a couple of sites on the old server that require PHP 5.6. I installed the relevant alt-php5.6 packages on the new Ubuntu server but I don't see a way to tell Apache to serve up pages for these sites using PHP 5.6. In fact, the alt-php56 packages don't seem to include an fpm package. Is there no way to serve up these sites anymore? They are for archival purposes and not generally accessible to the public so it would not be a huge loss but just want to be sure I'm not missing anything obvious before I write them off. Thanks.