diff --git a/Documentation/asciidoc.conf b/Documentation/asciidoc.conf
index 40d43b7..9fe70b2 100644
--- a/Documentation/asciidoc.conf
+++ b/Documentation/asciidoc.conf
@@ -24,7 +24,7 @@ ifdef::backend-docbook[]
 endif::backend-docbook[]
 
 ifdef::backend-docbook[]
-ifndef::docbook-xsl-172[]
+ifdef::docbook-xsl-168[]
 # "unbreak" docbook-xsl v1.68 for manpages. v1.69 works with or without this.
 # v1.72 breaks with this because it replaces dots not in roff requests.
 [listingblock]
@@ -39,7 +39,7 @@ ifdef::doctype-manpage[]
 endif::doctype-manpage[]
 </literallayout>
 {title#}</example>
-endif::docbook-xsl-172[]
+endif::docbook-xsl-168[]
 endif::backend-docbook[]
 
 ifdef::doctype-manpage[]