diff --git a/doc/doc_requirements.txt b/doc/doc_requirements.txt
index 23186a2..044645d 100644
--- a/doc/doc_requirements.txt
+++ b/doc/doc_requirements.txt
@@ -3,7 +3,7 @@ Babel==2.9.1
 certifi==2019.6.16
 chardet==3.0.4
 docutils==0.15.2
-idna==2.8
+idna==3.7
 imagesize==1.1.0
 Jinja2==2.11.3
 MarkupSafe==1.1.1