5.2.4 changed some internals that cause problems with this Option in EA3. At this time, using PHP 5.2.4 in a concurrent PHP setup is not recommended if you rely upon any zend_extension. This includes extensions such as Zend Optimizer and ioncube. These setups cause errors like: Code: /usr/local/ioncube/ioncube_loader_lin_5.2_ts.so doesn't appear to be a valid Zend extension /usr/local/Zend/lib/ZendExtensionManager_TS.so doesn't appear to be a valid Zend extension Likewise, at this time, Suhosin is not compatible with a Concurrent PHP set. It is only built against PHP 4, but installed for use with PHP 5. We are currently working to address these issues.