diff --git a/README.md b/README.md
index 2e62182..4b26258 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ This plugin provides a [Mailgun](http://www.mailgun.com/) integration for [Craft
 
 ## Requirements
 
-This plugin requires Craft CMS 3.1.0 or later.
+This plugin requires Craft CMS 3.1.5 or later.
 
 You can install this plugin from the Plugin Store or with Composer.
 
diff --git a/composer.json b/composer.json
index 7282993..f102c6a 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
     "rss": "https://github.com/craftcms/mailgun/commits/master.atom"
   },
   "require": {
-    "craftcms/cms": "^3.1.0",
+    "craftcms/cms": "^3.1.5",
     "cspoo/swiftmailer-mailgun-bundle": "^1.0.0",
     "php-http/guzzle6-adapter": "^1.1.1"
   },
diff --git a/src/templates/settings.html b/src/templates/settings.html
index be6fb0b..4b040a3 100644
--- a/src/templates/settings.html
+++ b/src/templates/settings.html
@@ -6,7 +6,7 @@
     instructions: "The domain to send email from."|t('mailgun'),
     id: 'domain',
     name: 'domain',
-    suggestions: craft.cp.getEnvSuggestions(),
+    suggestEnvVars: true,
     value: adapter.domain,
     errors: adapter.getErrors('domain')
 }) }}
@@ -17,7 +17,7 @@
     instructions: "You can find this in your Mailgun settings for the chosen domain."|t('mailgun'),
     id: 'apiKey',
     name: 'apiKey',
-    suggestions: craft.cp.getEnvSuggestions(),
+    suggestEnvVars: true,
     value: adapter.apiKey,
     errors: adapter.getErrors('apiKey')
 }) }}
@@ -27,7 +27,7 @@
     instructions: "You can find this in your Mailgun settings for the chosen domain."|t('mailgun'),
     id: 'endpoint',
     name: 'endpoint',
-    suggestions: craft.cp.getEnvSuggestions(),
+    suggestEnvVars: true,
     placeholder: 'https://api.mailgun.net',
     value: adapter.endpoint,
     errors: adapter.getErrors('endpoint')