diff --git a/src/php/src/Front/Api/ApiVersionService.php b/src/php/src/Front/Api/ApiVersionService.php
index 5b889d2..2e23593 100644
--- a/src/php/src/Front/Api/ApiVersionService.php
+++ b/src/php/src/Front/Api/ApiVersionService.php
@@ -54,6 +54,69 @@ use Illuminate\Http\Request;
  */
 class ApiVersionService
 {
+    /**
+     * Normalise a list of API versions to unique positive integers.
+     *
+     * @param  array<int|string, mixed>  $versions
+     * @return array<int>
+     */
+    protected function normaliseVersions(array $versions): array
+    {
+        $normalised = [];
+
+        foreach ($versions as $version) {
+            if (! is_numeric($version)) {
+                continue;
+            }
+
+            $version = (int) $version;
+            if ($version <= 0) {
+                continue;
+            }
+
+            $normalised[] = $version;
+        }
+
+        return array_values(array_unique($normalised));
+    }
+
+    /**
+     * Normalise sunset dates to an integer-keyed map.
+     *
+     * @param  array<int|string, mixed>  $sunsets
+     * @return array<int, string>
+     */
+    protected function normaliseSunsetDates(array $sunsets): array
+    {
+        $normalised = [];
+
+        foreach ($sunsets as $version => $date) {
+            if (! is_numeric($version)) {
+                continue;
+            }
+
+            $version = (int) $version;
+            if ($version <= 0) {
+                continue;
+            }
+
+            if ($date === null) {
+                continue;
+            }
+
+            $date = trim((string) $date);
+            if ($date === '') {
+                continue;
+            }
+
+            $normalised[$version] = $date;
+        }
+
+        ksort($normalised);
+
+        return $normalised;
+    }
+
     /**
      * Get the current API version from the request.
      *
@@ -116,7 +179,7 @@ class ApiVersionService
     public function isDeprecated(?Request $request = null): bool
     {
         $current = $this->current($request);
-        $deprecated = config('api.versioning.deprecated', []);
+        $deprecated = $this->deprecatedVersions();
 
         return $current !== null && in_array($current, $deprecated, true);
     }
@@ -144,7 +207,7 @@ class ApiVersionService
      */
     public function supportedVersions(): array
     {
-        return config('api.versioning.supported', [1]);
+        return $this->normaliseVersions((array) config('api.versioning.supported', [1]));
     }
 
     /**
@@ -154,7 +217,7 @@ class ApiVersionService
      */
     public function deprecatedVersions(): array
     {
-        return config('api.versioning.deprecated', []);
+        return $this->normaliseVersions((array) config('api.versioning.deprecated', []));
     }
 
     /**
@@ -164,7 +227,7 @@ class ApiVersionService
      */
     public function sunsetDates(): array
     {
-        return config('api.versioning.sunset', []);
+        return $this->normaliseSunsetDates((array) config('api.versioning.sunset', []));
     }
 
     /**
diff --git a/src/php/tests/Feature/ApiVersionServiceTest.php b/src/php/tests/Feature/ApiVersionServiceTest.php
new file mode 100644
index 0000000..b9b299d
--- /dev/null
+++ b/src/php/tests/Feature/ApiVersionServiceTest.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+use Core\Front\Api\ApiVersionService;
+use Illuminate\Support\Facades\Config;
+
+beforeEach(function () {
+    Config::set('api.versioning.default', 1);
+    Config::set('api.versioning.current', 2);
+    Config::set('api.versioning.supported', [1, 2]);
+    Config::set('api.versioning.deprecated', []);
+    Config::set('api.versioning.sunset', []);
+});
+
+it('normalises configured versions before reading them', function () {
+    Config::set('api.versioning.supported', ['1', '02', '2', 'ignored', 0, -1]);
+    Config::set('api.versioning.deprecated', ['1', '3', '3']);
+    Config::set('api.versioning.sunset', [
+        '1' => '2025-06-01',
+        '02' => '2025-12-31',
+        'ignored' => '2026-01-01',
+        0 => '2024-01-01',
+        -1 => '2024-06-01',
+        3 => '',
+    ]);
+
+    $versions = new ApiVersionService();
+
+    expect($versions->supportedVersions())->toBe([1, 2]);
+    expect($versions->deprecatedVersions())->toBe([1, 3]);
+    expect($versions->sunsetDates())->toBe([
+        1 => '2025-06-01',
+        2 => '2025-12-31',
+    ]);
+    expect($versions->isSupported(1))->toBeTrue();
+    expect($versions->isSupported(2))->toBeTrue();
+    expect($versions->isSupported(3))->toBeFalse();
+    expect($versions->isDeprecated())->toBeFalse();
+});