diff --git a/requirements.txt b/requirements.txt
index 5211f3ce2bff6d4859cb9a6fef5fa3d21f859945..a4a2ec173b1cbfae0b60efd669039a9baaba6a8a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-twisted>=21.2.0
+twisted>=21.2.0,<21.7.0
 twistar>=2.0
 psycopg2>=2.9,<2.10 --no-binary psycopg2
 pyOpenSSL>=17.5.0