diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index a47b1631fc31..4d0869ef4ade 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -167,8 +167,8 @@ def send_request(**kwargs):
                 # have a good idea that the request has either succeeded or failed on
                 # the master, and so whether we should clean up or not.
                 while True:
-                    headers = Headers()
-                    opentracing.inject_active_span_twisted_headers(
+                    headers = {}
+                    opentracing.inject_active_span_byte_dict(
                         headers, None, check_destination=False
                     )
                     try: