diff --git a/setup.cfg b/setup.cfg
index 919dc50..d87d6aa 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -17,6 +17,7 @@ install_requires =
     debts==0.5
     emails==0.6
     Weasyprint==51
+    MarkupSafe==2.0.1
 
 [options.extras_require]
 dev =