diff --git a/book/external/Sphinx-Image-Inverter b/book/external/Sphinx-Image-Inverter
index 6789ae2..20d8d6d 160000
--- a/book/external/Sphinx-Image-Inverter
+++ b/book/external/Sphinx-Image-Inverter
@@ -1 +1 @@
-Subproject commit 6789ae2128e183874f758b05b897580aba587689
+Subproject commit 20d8d6d1280edbb2e6df9639fe66c28b58d2e63c