diff --git a/class/wysiwyg.php b/class/wysiwyg.php
index 34ce8fd..42eb9bd 100644
--- a/class/wysiwyg.php
+++ b/class/wysiwyg.php
@@ -77,7 +77,7 @@ class MCI_Footnotes_WYSIWYG {
 			$l_str_starting_tag = MCI_Footnotes_Settings::instance()->get( MCI_Footnotes_Settings::C_STR_FOOTNOTES_SHORT_CODE_START_USER_DEFINED );
 			$l_str_ending_tag = MCI_Footnotes_Settings::instance()->get( MCI_Footnotes_Settings::C_STR_FOOTNOTES_SHORT_CODE_END_USER_DEFINED );
 		}
-		echo json_encode(
+		echo wp_json_encode(
 			array(
 				'start' => htmlspecialchars( $l_str_starting_tag ),
 				'end' => htmlspecialchars( $l_str_ending_tag ),