diff --git a/Makefile b/Makefile
index ef44b5acbee78f1303f2d082bfd103da272768af..c33dc29b227e8e658f8086b085f126d4143617e8 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 BASE=ordernumbers
 PLATTFORM=woocommerce
 VENDOR=opentools
-VERSION=1.3.5
+VERSION=1.3.6
 DIR = $(shell pwd)
 SVNDIR=wordpress-plugin-svn
 
diff --git a/assets/js/opentools-updatecheck.js b/assets/js/opentools-updatecheck.js
index 74773fcc8c7c3c0cd57d6e8c4390a04a4b2eab04..3f8f4070aaa8e16f9f2dfa098720026385a14d28 100644
--- a/assets/js/opentools-updatecheck.js
+++ b/assets/js/opentools-updatecheck.js
@@ -9,7 +9,7 @@ var showUpdateCredentialsRow = function (btn) {
 		type: "POST",
 		url: ajaxurl,
 		data: {
-			action: 'getUpdateCredentialsRow',
+			action: 'getUpdateCredentialsRow_'+slug,
 			slug: slug,
 			_ajax_nonce: nonce
 		},
@@ -32,7 +32,7 @@ var submitUpdateCredentials = function(btn) {
 	
 	var tr = jQuery(btn).closest('tr');
 	var data = { 
-			action: 'submitUpdateCredentials',
+			action: 'submitUpdateCredentials_'+slug,
 			slug: slug,
 			_ajax_nonce: nonce,
 		};
diff --git a/opentools-update-checker.php b/opentools-update-checker.php
index c14931614456e2b484161afbfcfce2f6feb19fdf..b01fa1d8b1dd2cf0a9f89de7d11f840cb2aeb00d 100644
--- a/opentools-update-checker.php
+++ b/opentools-update-checker.php
@@ -42,8 +42,8 @@ class OpenToolsPluginUpdateChecker extends PluginUpdateChecker_2_1 {
 // 		add_filter('plugin_row_meta', array($this, 'displayUpdateCredentialsLink'), 9, 2);
 		add_filter('plugin_action_links_'.$this->pluginFile, array($this, 'displayUpdateCredentialsLink'), 9, 2);
 
-		add_action( 'wp_ajax_getUpdateCredentialsRow',		array( &$this, 'getUpdateCredentialsRow') );
-		add_action( 'wp_ajax_submitUpdateCredentials',		array( &$this, 'submitUpdateCredentials') );
+		add_action( 'wp_ajax_getUpdateCredentialsRow_'.$this->slug,		array( &$this, 'getUpdateCredentialsRow') );
+		add_action( 'wp_ajax_submitUpdateCredentials_'.$this->slug,		array( &$this, 'submitUpdateCredentials') );
 	}
 
 	protected function getCredentials($slug) 
@@ -123,13 +123,26 @@ class OpenToolsPluginUpdateChecker extends PluginUpdateChecker_2_1 {
 	*/
 	public function getUpdateCredentialsRow() {
 		$json = array('row' => '', 'message'=>'Unsuccessful');
+		if (isset($_REQUEST['slug']) && $_REQUEST['slug'] != $this->slug) {
+			// This update checker is not responsible. Action is for another plugin
+			return;
+		}
 		
+ $json['showCredentials'] = $showCredentials;
+ $json['issetSLUG'] = isset($_REQUEST['slug']);
+ $json['SLUGmatches'] = $_REQUEST['slug'] == $this->slug;
+ $json['userCanUpdatePlugins'] = current_user_can('update_plugins');
+ $json['checkAjax'] = check_ajax_referer('otup_enter_update_credentials');
+ $json['NotEmptyCredVars'] = !empty($this->credvars);
+
+ $json['IsNetworkAdmin'] = is_network_admin();
+ $json['isMultisite'] = is_multisite();
 		$showCredentials = isset($_REQUEST['slug'])
 			&& $_REQUEST['slug'] == $this->slug
 			&& current_user_can('update_plugins')
-			&& check_ajax_referer('otup_enter_update_credentials');
-		$showCredentials = $showCredentials && !empty($this->credvars);
-			
+			&& check_ajax_referer('otup_enter_update_credentials')
+			&& !empty($this->credvars);
+		
 		if ( $showCredentials && (is_network_admin() || !is_multisite() )) {
 			$slug = $this->slug;
 			if ( is_network_admin() ) {
@@ -175,10 +188,15 @@ class OpenToolsPluginUpdateChecker extends PluginUpdateChecker_2_1 {
 	 * @return void
 	 */
 	public function submitUpdateCredentials() {
+		if (isset($_REQUEST['slug']) && $_REQUEST['slug'] != $this->slug) {
+			// This update checker is not responsible. Action is for another plugin
+			return;
+		}
+		
 		$json = array('message' => '', 'success' => FALSE);
 		$slug = isset($_REQUEST['slug'])?($_REQUEST['slug']):"INVALIDSLUG";
-		
-		$submitCredentials = $slug == $this->slug
+
+		$submitCredentials = ($slug == $this->slug)
 			&& current_user_can('update_plugins')
 			&& check_ajax_referer('otup_enter_update_credentials_'.$slug);
 		$submitCredentials = $submitCredentials && !empty($this->credvars);
diff --git a/ordernumbers_woocommerce_basic.php b/ordernumbers_woocommerce_basic.php
index 52c7fd1953ba9f7b3d3d4db38e2b2530826e7030..b5e334b23584dea5723d300c4797392ad24bc48e 100644
--- a/ordernumbers_woocommerce_basic.php
+++ b/ordernumbers_woocommerce_basic.php
@@ -510,7 +510,7 @@ class OpenToolsOrdernumbersBasic {
 			return $stored_number;
 		} else {
 			// No order number was created for this order, so simply use the orderid as default.
-			return $default;
+			return $orderid;
 		}
 	}
 
diff --git a/readme.txt b/readme.txt
index 6d339a27e76a2e905b133825fc1f01215e9c4240..799b1149c36c54a29bea4e581e89e3de06c10edd 100644
--- a/readme.txt
+++ b/readme.txt
@@ -4,7 +4,7 @@ Contributors: opentools
 Tags: WooCommerce, Order numbers, orders
 Requires at least: 4.0
 Tested up to: 4.5
-Stable tag: 1.3.5
+Stable tag: 1.3.6
 License: GPLv3 or later
 License URI: http://www.gnu.org/licenses/gpl.html
 
@@ -78,6 +78,9 @@ The Advanced Ordernumbers for WooCommerce plugin supports some invoicing plugins
 
 == Changelog ==
 
+= 1.3.6 =
+* Fix order number display for old orders
+
 = 1.3.5 =
 * Added variables [MonthName], [MonthName3], [Week], [WeekNumberYear], [DayOfYear], [Weekday], [WeekdayName], [WeekdayName3] (advanced version only)
 
diff --git a/releases/opentools-woocommerce-ordernumbers-advanced_v1.3.6.zip b/releases/opentools-woocommerce-ordernumbers-advanced_v1.3.6.zip
new file mode 100644
index 0000000000000000000000000000000000000000..9476dc14045959503d20f80b584fcfd20a69f9ad
Binary files /dev/null and b/releases/opentools-woocommerce-ordernumbers-advanced_v1.3.6.zip differ
diff --git a/releases/opentools-woocommerce-ordernumbers-basic_v1.3.6.zip b/releases/opentools-woocommerce-ordernumbers-basic_v1.3.6.zip
new file mode 100644
index 0000000000000000000000000000000000000000..d23d9aac04f8e75b9710b182ec2499ae622b672c
Binary files /dev/null and b/releases/opentools-woocommerce-ordernumbers-basic_v1.3.6.zip differ
diff --git a/woocommerce-advanced-ordernumbers.php b/woocommerce-advanced-ordernumbers.php
index eb85a6634d43478794438ec94f47e9f6edf91776..2b26026f69df23fdcf7eb9b0b014ab3c2482b708 100644
--- a/woocommerce-advanced-ordernumbers.php
+++ b/woocommerce-advanced-ordernumbers.php
@@ -3,7 +3,7 @@
  * Plugin Name: Woocommerce Advanced Ordernumbers
  * Plugin URI: http://open-tools.net/woocommerce/advanced-ordernumbers-for-woocommerce.html
  * Description: Lets the user freely configure the order numbers in WooCommerce.
- * Version: 1.3.5
+ * Version: 1.3.6
  * Author: Open Tools
  * Author URI: http://open-tools.net
  * Text Domain: woocommerce-advanced-ordernumbers
diff --git a/woocommerce-basic-ordernumbers.php b/woocommerce-basic-ordernumbers.php
index 4c9f563b448b69dfa2278354986637c2571f8bca..0af7009d993c938c0e0911639c38553c2984fcca 100644
--- a/woocommerce-basic-ordernumbers.php
+++ b/woocommerce-basic-ordernumbers.php
@@ -3,7 +3,7 @@
  * Plugin Name: WooCommerce Basic Ordernumbers
  * Plugin URI: http://open-tools.net/woocommerce/advanced-ordernumbers-for-woocommerce.html
  * Description: Configure WooCommerce ordernumbers to have a running counter and arbitrary, fixed text (prefix / postfix).
- * Version: 1.3.5
+ * Version: 1.3.6
  * Author: Open Tools
  * Author URI: http://open-tools.net
  * Text Domain: woocommerce-advanced-ordernumbers