diff --git a/src/epub/content.opf b/src/epub/content.opf
index a8e96d1..5718788 100644
--- a/src/epub/content.opf
+++ b/src/epub/content.opf
@@ -22,8 +22,8 @@
 		<meta property="schema:accessibilityFeature">alternativeText</meta>
 		<meta property="schema:accessibilityFeature">longDescription</meta>
 		<meta property="schema:accessibilityFeature">readingOrder</meta>
-		<meta property="schema:accessibilityFeature">structuralNavigation</meta>
 		<meta property="schema:accessibilityFeature">tableOfContents</meta>
+		<meta property="schema:accessibilityFeature">unlocked</meta>
 		<meta property="schema:accessibilityHazard">none</meta>
 		<meta property="schema:accessibilitySummary">This publication conforms to WCAG 2.1 Level AA.</meta>
 		<link href="onix.xml" media-type="application/xml" properties="onix" rel="record"/>