Log in to your server as the root using ssh to your server.
Type the following commands:
# cd /scripts # ./updatenow # ./easyapache
Follow on screen recommendations to recover Apache for CPanel server under Linux. Please note that you can see a choice on display asking you which option you would like built into your apache set up. Select options as per your requirements. Once it has completed it will immediately restart Apache for you and you will then be able to use the new features.
If you want to rebuild Apache configuration files on the Plesk server, you can check my post on Rebuild Apache.