diff --git a/jetforce/server.py b/jetforce/server.py
index ce5fcc7..fa2f6dc 100644
--- a/jetforce/server.py
+++ b/jetforce/server.py
@@ -103,7 +103,7 @@ class GeminiServer(Factory):
         It builds the instance of the protocol class, which is what actually
         implements the Gemini protocol.
         """
-        return GeminiProtocol(self, self.app)
+        return self.__class__.protocol_class(self, self.app)
 
     def initialize(self) -> None:
         """