diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 431f3be..b744b39 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,7 +24,7 @@ jobs:
         run: echo "::set-output name=dir::$(composer config cache-files-dir)"
 
       - name: Load Composer cache
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: ${{ steps.composer-cache.outputs.dir }}
           key: ${{ runner.os }}-${{ matrix.php }}-${{ matrix.deps }}-composer
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ce38567..fbcd4cf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,8 @@
 # Changelog
+## Unreleased
+### BREAKING
+- Add QueryArrayNormalizer middleware to ClientBuilder
+
 ## [v0.9.9] - 2024.06.06
 ### Added
 - Add support to API key authorization
diff --git a/composer.json b/composer.json
index 3877141..202d8a9 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
   },
   "scripts": {
     "test": [
-      "php-cs-fixer fix --dry-run -v",
+      "php-cs-fixer fix -v",
       "phpmd src text phpmd.xml.dist",
       "phpspec run --format=dot"
     ]
diff --git a/src/Client/ClientBuilder.php b/src/Client/ClientBuilder.php
index 4194b21..bf98a2b 100644
--- a/src/Client/ClientBuilder.php
+++ b/src/Client/ClientBuilder.php
@@ -7,6 +7,7 @@
 use GuzzleHttp\HandlerStack;
 use Omikron\FactFinder\Communication\Client\Middleware\Authenticator;
 use Omikron\FactFinder\Communication\Client\Middleware\HttpErrors;
+use Omikron\FactFinder\Communication\Client\Middleware\QueryArrayNormalizer;
 use Omikron\FactFinder\Communication\Credentials;
 use Omikron\FactFinder\Communication\ServerUrl;
 use Omikron\FactFinder\Communication\Version;
@@ -57,6 +58,7 @@ public function build(): ClientInterface
     {
         $handler = HandlerStack::create();
         $handler->push(new HttpErrors());
+        $handler->push(new QueryArrayNormalizer());
 
         $config = [
             'base_uri'    => $this->serverUrl,
diff --git a/src/Client/Middleware/QueryArrayNormalizer.php b/src/Client/Middleware/QueryArrayNormalizer.php
new file mode 100644
index 0000000..48e2b84
--- /dev/null
+++ b/src/Client/Middleware/QueryArrayNormalizer.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Omikron\FactFinder\Communication\Client\Middleware;
+
+use Psr\Http\Message\RequestInterface;
+
+class QueryArrayNormalizer
+{
+    public function __invoke(callable $handler)
+    {
+        return function (RequestInterface $request, array $options) use ($handler) {
+
+            $uri   = $request->getUri();
+            $query = $uri->getQuery();
+
+            if (!$query) {
+                return $handler($request, $options);
+            }
+
+            parse_str($query, $params);
+
+            $normalized = [];
+
+            foreach ($params as $key => $value) {
+                if (is_array($value)) {
+                    foreach ($value as $v) {
+                        $normalized[] = rawurlencode($key) . '=' . rawurlencode((string) $v);
+                    }
+
+                    continue;
+                }
+
+                $normalized[] = rawurlencode($key) . '=' . rawurlencode((string) $value);
+            }
+
+            $newQuery = implode('&', $normalized);
+
+            $request = $request->withUri(
+                $uri->withQuery($newQuery)
+            );
+
+            return $handler($request, $options);
+        };
+    }
+}