diff --git a/Dockerfile b/Dockerfile
index 97e9951..0b5d20b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM docker.io/asciidoctor/docker-asciidoctor:1.55.0
+FROM docker.io/asciidoctor/docker-asciidoctor:1.56.0
 
 COPY theme /theme
 COPY fonts /theme/fonts