diff --git a/docs/requirements.txt b/docs/requirements.txt
index 91af786..a525f0f 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -18,7 +18,7 @@ cycler==0.11.0
     # via matplotlib
 docutils==0.20.1
     # via sphinx
-fonttools==4.40.0
+fonttools==4.43.0
     # via matplotlib
 idna==3.4
     # via requests