diff --git a/mailgun.php b/mailgun.php
index 5085dae..7c498c0 100755
--- a/mailgun.php
+++ b/mailgun.php
@@ -4,7 +4,7 @@
  * Plugin Name:  Mailgun
  * Plugin URI:   http://wordpress.org/extend/plugins/mailgun/
  * Description:  Mailgun integration for WordPress
- * Version:      1.8.0
+ * Version:      1.8.1
  * Author:       Mailgun
  * Author URI:   http://www.mailgun.com/
  * License:      GPLv2 or later
@@ -327,7 +327,7 @@ public function add_list()
      * @throws JsonException
      * @since    0.1
      */
-    public function list_form(string $list_address, array $args = [], array $instance = []): void
+    public function list_form(string $list_address, array $args = [], array $instance = [])
     {
         $widget_class_id = "mailgun-list-widget-{$args['widget_id']}";
         $form_class_id = "list-form-{$args['widget_id']}";
@@ -491,7 +491,7 @@ public function build_list_form(array $atts): string
      *
      * @since    0.1
      */
-    public function load_list_widget(): void
+    public function load_list_widget()
     {
         register_widget('list_widget');
         add_shortcode('mailgun', [&$this, 'build_list_form']);
diff --git a/readme.md b/readme.md
index 263bfc6..7325fea 100755
--- a/readme.md
+++ b/readme.md
@@ -5,7 +5,7 @@ Contributors: mailgun, sivel, lookahead.io, m35dev
 Tags: mailgun, smtp, http, api, mail, email
 Requires at least: 3.3
 Tested up to: 6.0.1
-Stable tag: 1.8.0
+Stable tag: 1.8.1
 License: GPLv2 or later
 
 
@@ -131,6 +131,9 @@ MAILGUN_FROM_ADDRESS Type: string
 
 
 == Changelog ==
+= 1.8.1 (2022-08-19): =
+- backward compatibility with php7.0
+
 = 1.8.0 (2022-08-18): =
 - Plugin refactoring. Using new languages constructions. Extended readme. Update version
 
diff --git a/readme.txt b/readme.txt
index 2306111..b2d740f 100755
--- a/readme.txt
+++ b/readme.txt
@@ -5,7 +5,7 @@ Contributors: mailgun, sivel, lookahead.io, m35dev
 Tags: mailgun, smtp, http, api, mail, email
 Requires at least: 3.3
 Tested up to: 6.0.1
-Stable tag: 1.8.0
+Stable tag: 1.8.1
 License: GPLv2 or later
 
 
@@ -128,6 +128,9 @@ MAILGUN_FROM_ADDRESS Type: string
 
 
 == Changelog ==
+= 1.8.1 (2022-08-19): =
+- backward compatibility with php7.0
+
 = 1.8.0 (2022-08-18): =
 - Plugin refactoring. Using new languages constructions. Extended readme. Update version