Plesk don't provide own PHP packages with Plesk, OS vendor packages are used. That's why you have an opportunity to upgrade your php version and add an additional extensions as you wish.
Plesk itself runs independently of server's PHP version. Latest Plesk version runs on PHP5. Therefore, if you can install PHP on Fedora, it will be fine with Plesk.
You simply download all needed PHP5 rpm packages and install them. One thing is you might also need this package to get rid of some dependencies error:
psa-phpx-configurator-xxx.noarch.rpm
It was compiled by Plesk developers. You can finв the package in the standart Plesk distributive.