diff --git a/requirements.txt b/requirements.txt
index 2fab040c8..b69264cdb 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,7 +1,7 @@
 certifi==2017.7.27.1
 chardet==3.0.4
 et-xmlfile==1.0.1
-idna==2.6
+idna==3.15
 jdcal==1.3
 numpy==1.13.1
 odfpy==1.3.5