diff --git a/requirements.txt b/requirements.txt
index d482f549..3fe7963d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -108,7 +108,7 @@ markupsafe==2.1.1
     #   jinja2
     #   mako
     #   wtforms
-marshmallow==3.18.0
+marshmallow==3.0.0
     # via
     #   marshmallow-enum
     #   teal