diff --git a/composer.json b/composer.json
index 300d547..8ffa641 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,7 @@
         "php": "^7.3 || ^8.0",
         "silverstripe/framework": "^4.10",
         "silverstripe/versioned": "^1.0",
-        "guzzlehttp/guzzle": "^6.3.3"
+        "guzzlehttp/guzzle": "^6.3.3 || ^7"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.5",
@@ -38,4 +38,4 @@
     },
     "minimum-stability": "dev",
     "prefer-stable": true
-}
\ No newline at end of file
+}
diff --git a/readme.md b/readme.md
index 699b352..daf38f6 100644
--- a/readme.md
+++ b/readme.md
@@ -16,7 +16,7 @@ This module adds an API for running environment checks to your API.
 ## Requirements
 
 * SilverStripe 4.x
-* PHP 5.6+
+* PHP 7.3
 
 For SilverStripe 3.x support, please use a `1.x` tagged release.
 
diff --git a/tests/Checks/CacheHeadersCheckTest.php b/tests/Checks/CacheHeadersCheckTest.php
index 9fe0a7a..0f3917d 100644
--- a/tests/Checks/CacheHeadersCheckTest.php
+++ b/tests/Checks/CacheHeadersCheckTest.php
@@ -55,7 +55,7 @@ class CacheHeadersCheckTest extends SapphireTest
             new Response(200, ['Cache-Control' => 'must-revalidate', 'ETag' => '123']),
             new Response(200, ['Cache-Control' =>'no-cache', 'ETag' => '123']),
             new Response(200, ['ETag' => '123']),
-            new Response(200, ['Cache-Control' =>'private, no-store', ' ETag' => '123']),
+            new Response(200, ['Cache-Control' =>'private, no-store', 'ETag' => '123']),
         ]);
 
         $handler = HandlerStack::create($mock);