diff --git a/RELEASE-NOTES-1.39 b/RELEASE-NOTES-1.39
index 44dfd21d090..db0a81fd5cb 100644
--- a/RELEASE-NOTES-1.39
+++ b/RELEASE-NOTES-1.39
@@ -451,6 +451,8 @@ because of Phabricator reports.
   warnings.
 * DifferenceEngine::textDiff(), deprecated in 1.32, now emits deprecation
   warnings.
+* FormatMetadata::flattenArrayContentLang(), deprecated in 1.36, now emits
+  deprecation warnings.
 * …
 
 === Other changes in 1.39 ===
diff --git a/includes/media/FormatMetadata.php b/includes/media/FormatMetadata.php
index e2f224b1fec..d3c983df0f2 100644
--- a/includes/media/FormatMetadata.php
+++ b/includes/media/FormatMetadata.php
@@ -1110,19 +1110,17 @@ class FormatMetadata extends ContextSource {
 	 * @param bool|IContextSource $context
 	 * @return string Single value (in wiki-syntax).
 	 * @since 1.23
-	 * @deprecated since 1.36, appears to have no callers
+	 * @deprecated since 1.36, appears to have no callers. Hard deprecated since 1.39.
 	 */
 	public static function flattenArrayContentLang( $vals, $type = 'ul',
 		$noHtml = false, $context = false
 	) {
+		wfDeprecated( __METHOD__, '1.36' );
 		// Allow $noHtml to be omitted.
 		if ( $noHtml instanceof IContextSource ) {
 			$context = $noHtml;
 			$noHtml = false;
 		}
-		if ( $noHtml ) {
-			wfDeprecated( __METHOD__ . ' with $noHtml = true', '1.36' );
-		}
 		$obj = new FormatMetadata;
 		if ( $context ) {
 			$obj->setContext( $context );