For Zend, type:
cd /usr/local/directadmin/custombuild
./build set zend yes
./build zend
after changing php versions, it’s recommended you install zend again.
Note that Zend Guard is the new name for Zend Optimizer, and is used for newer versions of php. Custombuild will install the correct one for your system.
For Ioncube, type:
cd /usr/local/directadmin/custombuild
./build set ioncube yes
./build ioncube
The “./build set” command only sets the option in the options.conf, so you only need to do that once to enable the feature, then install the item after it’s enabled.