diff --git a/requirements.txt b/requirements.txt
index 79263cad34694bf9bbceed90f7d7b968f3152cea..8c8c6fd140a364f25ecdcb7986397e3312e0aa98 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -10,5 +10,5 @@ wikitables
 pandas
 jupytext
 python-markdown-math
-mkdocs-material
+mkdocs-material<5
 ics