diff --git a/requirements.txt b/requirements.txt
index 882f2164..79d5616f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,5 @@
 pyyaml >= 5.1
-pydantic
+pydantic < 2
 numpy >= 1.17
 networkx
 frozendict