diff --git a/cmix/interface.go b/cmix/interface.go
index 1d0bfdaeb09c25ab4b26018233ab0b8b52e93964..a8d5df5250ca67c37d7b01f30c4620787678538f 100644
--- a/cmix/interface.go
+++ b/cmix/interface.go
@@ -191,6 +191,9 @@ type Client interface {
 	AddService(clientID *id.ID, newService message.Service,
 		response message.Processor)
 
+	// ChangeParallelNodeRegistration .
+	ChangeParallelNodeRegistration(num int) stoppable.Single
+
 	// DeleteService deletes a message service. If only a single response is
 	// associated with the preimage, the entire preimage is removed. If there is
 	// more than one response, only the given response is removed. If nil is