Add option to allow registrations that begin with '_' (#18262)

Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/synapse/config/registration.py b/synapse/config/registration.py

index 3cf7031656..8adf21079e 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -162,6 +162,10 @@ class RegistrationConfig(Config):
             "disable_msisdn_registration", False
         )
 
+        self.allow_underscore_prefixed_localpart = config.get(
+            "allow_underscore_prefixed_localpart", False
+        )
+
         session_lifetime = config.get("session_lifetime")
         if session_lifetime is not None:
             session_lifetime = self.parse_duration(session_lifetime)