diff --git a/archive-post-order-plus.php b/archive-post-order-plus.php
index bf1ef59..126b9d7 100644
--- a/archive-post-order-plus.php
+++ b/archive-post-order-plus.php
@@ -5,7 +5,7 @@ Plugin URI: https://develop.n-k-y.net/wordpress/wp_plugin/apop/
 Author: NBK45
 Author URI: https://develop.n-k-y.net
 Description: Archive Post Order Plus は「最新の投稿」「検索結果」「カテゴリー」「タグ」「カスタム分類」の投稿記事の表示順をドラッグで並べ替えて設定するプラグインです。
-Version: 1.1.9
+Version: 1.2.0
 License: GPLv2
 Text Domain: ArchivePostOrderPlus
 Domain Path: /languages
diff --git a/class/class.apop.apop_post.php b/class/class.apop.apop_post.php
index 962cc4f..527729d 100644
--- a/class/class.apop.apop_post.php
+++ b/class/class.apop.apop_post.php
@@ -92,7 +92,8 @@ if ( ! class_exists( 'APOP_POST' ) ) {
 			}
 
 			$archive_settings = get_option( '_apop_custompost_archive_sort_type' );
-			if ( array_key_exists( $post_type, $archive_settings ) && $archive_settings[ $post_type ] == 2 ) {
+			if ( $archive_settings && array_key_exists( $post_type, $archive_settings )
+			     && $archive_settings[ $post_type ] == 2 ) {
 				foreach ( $this->order_param_keys as $order_param_key ) {
 					if ( isset( $param[ $post_type ][ $order_param_key ]['field']['meta_key'] ) &&
 					     ! empty( $param[ $post_type ][ $order_param_key ]['field']['meta_key'] ) ) {
diff --git a/readme.txt b/readme.txt
index 2c4650f..5580803 100644
--- a/readme.txt
+++ b/readme.txt
@@ -2,9 +2,9 @@
 Contributors: nbk45
 Tags: latest posts order,categories post order,tags post order,custom taxonomy post order
 Requires at least: 4.9
-Tested up to: 5.8
+Tested up to: 5.9
 Requires PHP: 7.0
-Stable tag: 1.1.8
+Stable tag: 1.2.0
 License: GPLv2 or later
 License URI: https://www.gnu.org/licenses/gpl-2.0.html
 
@@ -82,6 +82,13 @@ screenshot-7.png
 screenshot-8.png
 
 == Changelog ==
+= 1.2.0 =
+confirm WordPress5.9
+Fixed Notice error in custom post archive.
+
+WordPress5.9動作確認
+カスタム投稿アーカイブのNoticeエラー修正
+
 = 1.1.9 =
 Changed the layout of the sort menu.
 Modified JavaScript variable declaration and stored element specification in variable.