diff --git a/classes/helpers/FrmAppHelper.php b/classes/helpers/FrmAppHelper.php
index 4fdaf8cbba..8638cd5f7d 100644
--- a/classes/helpers/FrmAppHelper.php
+++ b/classes/helpers/FrmAppHelper.php
@@ -4599,4 +4599,24 @@ public static function no_gdpr_cookies() {
 		$frm_settings = self::get_settings();
 		return $frm_settings->enable_gdpr && $frm_settings->no_gdpr_cookies;
 	}
+
+	/**
+	 * Check if a string is valid UTF-8.
+	 *
+	 * @since x.x
+	 *
+	 * @param string $string The string to check.
+	 * @return bool
+	 */
+	public static function is_valid_utf8( $string ) {
+		// wp_is_valid_utf8 is added in WP 6.9.
+		if ( function_exists( 'wp_is_valid_utf8' ) ) {
+			return wp_is_valid_utf8( $string );
+		}
+		// As of WP 6.9, seems_utf8 is deprecated.
+		if ( function_exists( 'seems_utf8' ) ) {
+			return seems_utf8( $string );
+		}
+		return false;
+	}
 }
diff --git a/classes/helpers/FrmXMLHelper.php b/classes/helpers/FrmXMLHelper.php
index 2a78ea95e8..4c63fe1bd2 100644
--- a/classes/helpers/FrmXMLHelper.php
+++ b/classes/helpers/FrmXMLHelper.php
@@ -1707,7 +1707,7 @@ public static function cdata( $str ) {
 		FrmAppHelper::unserialize_or_decode( $str );
 		if ( is_array( $str ) ) {
 			$str = json_encode( $str );
-		} elseif ( seems_utf8( $str ) === false ) {
+		} elseif ( FrmAppHelper::is_valid_utf8( $str ) === false ) {
 			$str = FrmAppHelper::maybe_utf8_encode( $str );
 		}