diff --git a/README.adoc b/README.adoc
index 791bbb3c..22666138 100644
--- a/README.adoc
+++ b/README.adoc
@@ -2,7 +2,7 @@
 :ASCIIDOCTOR_VERSION: 2.0.20
 :ASCIIDOCTOR_CONFLUENCE_VERSION: 0.0.2
 :ASCIIDOCTOR_PDF_VERSION: 2.3.9
-:ASCIIDOCTOR_DIAGRAM_VERSION: 2.2.12
+:ASCIIDOCTOR_DIAGRAM_VERSION: 2.2.13
 :ASCIIDOCTOR_EPUB3_VERSION: 1.5.1
 :ASCIIDOCTOR_FB2_VERSION: 0.7.0
 :ASCIIDOCTOR_MATHEMATICAL_VERSION: 0.3.5