1 files changed, 1 insertions, 0 deletions

diff --git a/synapse/api/constants.py b/synapse/api/constants.py

index a31f037748..a33ac34161 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -176,6 +176,7 @@ class RelationTypes:
     ANNOTATION = "m.annotation"
     REPLACE = "m.replace"
     REFERENCE = "m.reference"
+    THREAD = "io.element.thread"
 
 
 class LimitBlockingTypes: