diff --git a/Dockerfile b/Dockerfile
index 0138457..5d3a206 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -86,7 +86,7 @@ RUN apk add --no-cache \
   font-noto-cjk
 
 ARG asciidoctor_confluence_version=0.0.2
-ARG asciidoctor_diagram_version=2.3.0
+ARG asciidoctor_diagram_version=2.3.1
 ARG asciidoctor_epub3_version=2.1.3
 ARG asciidoctor_fb2_version=0.7.0
 ARG asciidoctor_mathematical_version=0.3.5