Q. Are there any recommended EPP-client libraries for connection to the Donuts SRS?
A. The registry SRS is designed to allow use of any standard EPP client that uses industry standard Extensible Provisioning Protocol (EPP) Domain Name Mapping ( http://tools.ietf.org/html/rfc5731).
Some registrars use the EPP-RTK- java, others uses the PHP EPP Toolkit, and others develop their own.
A registrar toolkit is at http://sourceforge.net/projects/epp-rtk/ and htpp://sourceforge.net/projects/epp-server/ is another other source of information.
We don't supply or provide support for specific EPP toolkits.