diff --git a/setup.py b/setup.py
index <HASH>..<HASH> 100644
--- a/setup.py
+++ b/setup.py
@@ -18,6 +18,7 @@ general_requirements = [
     ]
 
 api_requirements = [
+    'markupsafe == 2.0.1',  # While flask revision < 2
     'flask == 1.1.4',
     'flask-cors == 3.0.10',
     'gunicorn >= 20.0.0, < 21.0.0',
Fix MarkupSafe revision
As dependency of Flask <I> through Jinja2 <I>