diff --git a/src/Options.php b/src/Options.php
index 7c75f14..2608350 100644
--- a/src/Options.php
+++ b/src/Options.php
@@ -141,6 +141,10 @@ public function pre_update_option( $new_value, $old_value ): ?array {
 	 */
 	public static function get_defaults(): array {
 
+		if ( ! function_exists( 'is_plugin_active' ) ) {
+			include_once ABSPATH . 'wp-admin/includes/plugin.php';
+		}
+
 		$map = self::$map;
 
 		if ( \is_plugin_active( 'woocommerce/woocommerce.php' ) ) {