diff --git a/composer.json b/composer.json
index bc2d47b..e8a8ef5 100644
--- a/composer.json
+++ b/composer.json
@@ -19,16 +19,15 @@
         }
     ],
     "require": {
-        "php": "^7.4 || ^8.0",
-        "silverstripe/framework": "^4.10",
-        "silverstripe/reports": "^4.4",
-        "symbiote/silverstripe-queuedjobs": "^4.1",
-        "guzzlehttp/guzzle": "^6.3 || ^7.0"
+        "php": "^8.1",
+        "silverstripe/framework": "^5",
+        "silverstripe/reports": "^5",
+        "symbiote/silverstripe-queuedjobs": "^5"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.5",
         "squizlabs/php_codesniffer": "^3",
-        "symfony/thanks": "^1.0"
+        "symfony/thanks": "^1.2"
     },
     "autoload": {
         "psr-4": {
diff --git a/src/Util/ApiLoader.php b/src/Util/ApiLoader.php
index 65939b4..f6f05fd 100644
--- a/src/Util/ApiLoader.php
+++ b/src/Util/ApiLoader.php
@@ -134,7 +134,7 @@ public function getClientOptions()
      */
     protected function getFromCache()
     {
-        $cacheKey = $this->getCacheKey();
+        $cacheKey = $this->getCacheKey() ?? '';
         $result = $this->getCache()->get($cacheKey, false);
         if ($result === false) {
             return false;
@@ -155,6 +155,8 @@ protected function getFromCache()
      */
     protected function setToCache($cacheKey, $value, $ttl = null)
     {
+        $cacheKey = $cacheKey ?? '';
+        
         // Seralize as JSON to ensure array etc can be stored
         $value = json_encode($value);
 
diff --git a/tests/Util/ApiLoaderTest.php b/tests/Util/ApiLoaderTest.php
index 023ff2d..9ca6e74 100644
--- a/tests/Util/ApiLoaderTest.php
+++ b/tests/Util/ApiLoaderTest.php
@@ -9,7 +9,7 @@
 use GuzzleHttp\HandlerStack;
 use GuzzleHttp\Psr7\Response;
 use SilverStripe\Dev\SapphireTest;
-use Symfony\Component\Cache\Simple\NullCache;
+use Psr\SimpleCache\CacheInterface;
 
 class ApiLoaderTest extends SapphireTest
 {
@@ -88,9 +88,7 @@ public function testCacheControlSettingsAreRespected()
     {
         $fakeAddons = ['foo/bar', 'bin/baz'];
 
-        $cacheMock = $this->getMockBuilder(NullCache::class)
-            ->setMethods(['get', 'set'])
-            ->getMock();
+        $cacheMock = $this->getMockCacheInterface();
 
         $cacheMock->expects($this->once())->method('get')->will($this->returnValue(false));
         $cacheMock->expects($this->once())
@@ -114,9 +112,7 @@ public function testCachedAddonsAreUsedWhenAvailable()
     {
         $fakeAddons = ['foo/bar', 'bin/baz'];
 
-        $cacheMock = $this->getMockBuilder(NullCache::class)
-            ->setMethods(['get', 'set'])
-            ->getMock();
+        $cacheMock = $this->getMockCacheInterface();
 
         $cacheMock->expects($this->once())->method('get')->will($this->returnValue(json_encode($fakeAddons)));
         $loader = $this->getLoader($cacheMock);
@@ -153,9 +149,7 @@ protected function getMockClient(Response $withResponse)
     protected function getLoader($cacheMock = false)
     {
         if (!$cacheMock) {
-            $cacheMock = $this->getMockBuilder(NullCache::class)
-                ->setMethods(['get', 'set'])
-                ->getMock();
+            $cacheMock = $this->getMockCacheInterface();
 
             $cacheMock->expects($this->any())->method('get')->will($this->returnValue(false));
             $cacheMock->expects($this->any())->method('set')->will($this->returnValue(true));
@@ -168,4 +162,14 @@ protected function getLoader($cacheMock = false)
 
         return $loader;
     }
+
+    protected function getMockCacheInterface()
+    {
+        $methods = ['get', 'set', 'has', 'delete', 'getMultiple', 'setMultiple', 'clear', 'deleteMultiple'];
+        $mock = $this->getMockBuilder(CacheInterface::class)
+            ->setMethods($methods)
+            ->getMock();
+
+        return $mock;
+    }
 }