diff --git a/requirements.txt b/requirements.txt
index 25a3325..e0559d4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,7 @@ sphinx-image-inverter == 1.1.2
 sphinx-exercise == 1.0.1
 sphinx-proof == 0.2.0
 sphinx-named-colors == 1.0.1
-sphinx-iframes == 1.0.1
+sphinx-iframes == 1.0.3
 sphinx-prime-applets == 1.0.1
 
 git+https://github.com/TeachBooks/Sphinx-Thebe