diff --git a/backend/python/chatterbox/requirements.txt b/backend/python/chatterbox/requirements.txt
index 55a0867f0..b379973f5 100644
--- a/backend/python/chatterbox/requirements.txt
+++ b/backend/python/chatterbox/requirements.txt
@@ -3,4 +3,7 @@ protobuf
 certifi
 packaging
 setuptools
-poetry
\ No newline at end of file
+poetry
+# Pin a modern omegaconf so pip doesn't backtrack to 1.x — old 1.x sdists
+# pull ruamel.yaml<0.15 whose setup.py is Python-2-only and fails to build.
+omegaconf>=2.0
\ No newline at end of file