A new version of OS X was release yesterday, and we have provided a fix to PAServer for 10 Seattle to offer full support for El Capitan. 

The downlaod is at  cc.embarcadero.com/item/30398  and is offers also some improvements in iOS 9 support (you can now use the latest SDK to target older versions of iOS). Read more on Sarina's blog at community.embarcadero.com/blogs/entry/paserver-hotfix-for-rad-studio-10-seattle-ios-9-and-os-x-el-capitan.

For iOS 9 support you can also read community.embarcadero.com/blogs/entry/how-to-use-custom-info-plist-xml-to-support-ios-9-s-new-app-transport-security-feature and (if you are not using 10 Seattle) community.embarcadero.com/blogs/entry/workaround-steps-for-building-ios-32-bit-applications-for-ios-9-with-xe7-and-xe8.