diff --git a/config/firebase.php b/config/firebase.php
index bf33b63..10118ee 100644
--- a/config/firebase.php
+++ b/config/firebase.php
@@ -16,7 +16,6 @@
      * ------------------------------------------------------------------------
      */
     'projects' => [
-
         'app' => [
             /*
              * ------------------------------------------------------------------------
@@ -47,7 +46,6 @@
              * first time you try to access a component of the Firebase Admin SDK.
              *
              */
-
             'credentials' => env('FIREBASE_CREDENTIALS', env('GOOGLE_APPLICATION_CREDENTIALS')),
 
             /*
@@ -93,7 +91,6 @@
             ],
 
             'dynamic_links' => [
-
                 /*
                  * Dynamic links can be built with any URL prefix registered on
                  *
@@ -105,9 +102,7 @@
                  * The value must be a valid domain, for example,
                  * https://example.page.link
                  */
-
                 'default_domain' => env('FIREBASE_DYNAMIC_LINKS_DEFAULT_DOMAIN'),
-
             ],
 
             /*
@@ -117,7 +112,6 @@
              */
 
             'storage' => [
-
                 /*
                  * Your project's default storage bucket usually uses the project ID
                  * as its name. If you have multiple storage buckets and want to
@@ -126,7 +120,6 @@
                  */
 
                 'default_bucket' => env('FIREBASE_STORAGE_DEFAULT_BUCKET'),
-
             ],
 
             /*
@@ -185,7 +178,7 @@
                  */
                 'timeout' => env('FIREBASE_HTTP_CLIENT_TIMEOUT'),
 
-                // 'guzzle_middlewares' => [],
+                'guzzle_middlewares' => [],
             ],
         ],
     ],
diff --git a/src/FirebaseProjectManager.php b/src/FirebaseProjectManager.php
index 8845abd..3a0dbe8 100644
--- a/src/FirebaseProjectManager.php
+++ b/src/FirebaseProjectManager.php
@@ -6,7 +6,6 @@
 
 use Illuminate\Contracts\Container\Container;
 use Illuminate\Contracts\Foundation\Application;
-use Illuminate\Support\Arr;
 use Kreait\Firebase\Exception\InvalidArgumentException;
 use Kreait\Firebase\Factory;
 use Kreait\Firebase\Http\HttpClientOptions;
@@ -48,7 +47,7 @@ protected function configuration(string $name): array
         return $config;
     }
 
-    protected function resolveCredentials(string $credentials): string
+    protected function resolveJsonCredentials(string $credentials): string
     {
         $isJsonString = \str_starts_with($credentials, '{');
         $isAbsoluteLinuxPath = \str_starts_with($credentials, '/');
@@ -65,33 +64,31 @@ protected function configure(string $name): FirebaseProject
 
         $config = $this->configuration($name);
 
-        if ($tenantId = Arr::get($config, 'auth.tenant_id')) {
+        if ($tenantId = $config['auth']['tenant_id'] ?? null) {
             $factory = $factory->withTenantId($tenantId);
         }
 
-        if ($credentials = Arr::get($config, 'credentials.file', Arr::get($config, 'credentials'))) {
+        if ($credentials = $config['credentials']['file'] ?? ($config['credentials'] ?? null)) {
             if (is_string($credentials)) {
-                $factory = $factory->withServiceAccount($this->resolveCredentials($credentials));
+                $credentials = $this->resolveJsonCredentials($credentials);
             }
 
-            if (is_array($credentials) && Arr::has($credentials, ['type', 'project_id'])) {
-                $factory = $factory->withServiceAccount($credentials);
-            }
+            $factory = $factory->withServiceAccount($credentials);
         }
 
-        if ($databaseUrl = Arr::get($config, 'database.url')) {
+        if ($databaseUrl = $config['database']['url'] ?? null) {
             $factory = $factory->withDatabaseUri($databaseUrl);
         }
 
-        if ($authVariableOverride = Arr::get($config, 'database.auth_variable_override')) {
+        if ($authVariableOverride = $config['database']['auth_variable_override'] ?? null) {
             $factory = $factory->withDatabaseAuthVariableOverride($authVariableOverride);
         }
 
-        if ($defaultStorageBucket = Arr::get($config, 'storage.default_bucket')) {
+        if ($defaultStorageBucket = $config['storage']['default_bucket'] ?? null) {
             $factory = $factory->withDefaultStorageBucket($defaultStorageBucket);
         }
 
-        if ($cacheStore = Arr::get($config, 'cache_store')) {
+        if ($cacheStore = $config['cache_store'] ?? null) {
             $cache = $this->app->make('cache')->store($cacheStore);
 
             if ($cache instanceof CacheInterface) {
@@ -100,16 +97,18 @@ protected function configure(string $name): FirebaseProject
                 throw new InvalidArgumentException('The cache store must be an instance of a PSR-6 or PSR-16 cache');
             }
 
-            $factory = $factory->withVerifierCache($cache)->withAuthTokenCache($cache);
+            $factory = $factory
+                ->withVerifierCache($cache)
+                ->withAuthTokenCache($cache);
         }
 
-        if ($logChannel = Arr::get($config, 'logging.http_log_channel')) {
+        if ($logChannel = $config['logging']['http_log_channel'] ?? null) {
             $factory = $factory->withHttpLogger(
                 $this->app->make('log')->channel($logChannel)
             );
         }
 
-        if ($logChannel = Arr::get($config, 'logging.http_debug_log_channel')) {
+        if ($logChannel = $config['logging']['http_debug_log_channel'] ?? null) {
             $factory = $factory->withHttpDebugLogger(
                 $this->app->make('log')->channel($logChannel)
             );
@@ -117,15 +116,15 @@ protected function configure(string $name): FirebaseProject
 
         $options = HttpClientOptions::default();
 
-        if ($proxy = Arr::get($config, 'http_client_options.proxy')) {
+        if ($proxy = $config['http_client_options']['proxy'] ?? null) {
             $options = $options->withProxy($proxy);
         }
 
-        if ($timeout = Arr::get($config, 'http_client_options.timeout')) {
+        if ($timeout = $config['http_client_options']['timeout'] ?? null) {
             $options = $options->withTimeOut((float) $timeout);
         }
 
-        if ($middlewares = Arr::get($config, 'http_client_options.guzzle_middlewares')) {
+        if ($middlewares = $config['http_client_options']['guzzle_middlewares'] ?? null) {
             $options = $options->withGuzzleMiddlewares($middlewares);
         }
 
diff --git a/tests/FirebaseProjectManagerTest.php b/tests/FirebaseProjectManagerTest.php
index 54963b2..9e0d07d 100644
--- a/tests/FirebaseProjectManagerTest.php
+++ b/tests/FirebaseProjectManagerTest.php
@@ -84,6 +84,27 @@ public function credentials_can_be_configured_using_a_json_file(): void
         $this->assertSame($credentials, $serviceAccount);
     }
 
+    /**
+     * @test
+     */
+    public function json_file_credentials_can_be_used_using_the_deprecated_configuration_entry(): void
+    {
+        // Reference credentials
+        $credentialsPath = \realpath(__DIR__ . '/_fixtures/service_account.json');
+        $credentials = \json_decode(\file_get_contents($credentialsPath), true);
+
+        // Set configuration and retrieve project
+        $projectName = 'app';
+        $this->app->config->set('firebase.projects.' . $projectName . '.credentials.file', \realpath(__DIR__ . '/_fixtures/service_account.json'));
+        $factory = $this->factoryForProject($projectName);
+
+        // Retrieve service account
+        $serviceAccount = $this->getAccessibleProperty($factory, 'serviceAccount')->getValue($factory);
+
+        // Validate value
+        $this->assertSame($credentials, $serviceAccount);
+    }
+
     /**
      * @test
      */