diff --git a/app/config/collections/projects.php b/app/config/collections/projects.php
index a00e40b03a..64e53f6799 100644
--- a/app/config/collections/projects.php
+++ b/app/config/collections/projects.php
@@ -777,7 +777,6 @@ return [
                 'filters' => [],
             ],
             [
-                // At the moment, always empty (no runtime supports it yet)
                 'array' => false,
                 '$id' => ID::custom('startCommand'),
                 'type' => Database::VAR_STRING,
diff --git a/src/Appwrite/Utopia/Response/Filters/V21.php b/src/Appwrite/Utopia/Response/Filters/V21.php
index c825b3df56..aff2536456 100644
--- a/src/Appwrite/Utopia/Response/Filters/V21.php
+++ b/src/Appwrite/Utopia/Response/Filters/V21.php
@@ -32,6 +32,7 @@ class V21 extends Filter
     protected function parseSite(array $content): array
     {
         $content = $this->parseSpecs($content);
+        unset($content['startCommand']);
         return $content;
     }
 
@@ -46,6 +47,7 @@ class V21 extends Filter
         $content['specification'] = $content['buildSpecification'] ?? null;
         unset($content['buildSpecification']);
         unset($content['runtimeSpecification']);
+        unset($content['deploymentRetention']);
         return $content;
     }
 }
diff --git a/tests/unit/Utopia/Response/Filters/V21Test.php b/tests/unit/Utopia/Response/Filters/V21Test.php
new file mode 100644
index 0000000000..0e5bfb9c55
--- /dev/null
+++ b/tests/unit/Utopia/Response/Filters/V21Test.php
@@ -0,0 +1,190 @@
+<?php
+
+namespace Tests\Unit\Utopia\Response\Filters;
+
+use Appwrite\Utopia\Response;
+use Appwrite\Utopia\Response\Filters\V21;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+class V21Test extends TestCase
+{
+    /**
+     * @var Filter
+     */
+    protected $filter = null;
+
+    public function setUp(): void
+    {
+        $this->filter = new V21();
+    }
+
+    public function tearDown(): void
+    {
+    }
+
+    public static function functionProvider(): array
+    {
+        return [
+            'convert buildSpecification to specification and remove new fields' => [
+                [
+                    'buildSpecification' => 's-1vcpu-512mb',
+                    'runtimeSpecification' => 's-1vcpu-512mb',
+                    'deploymentRetention' => 7,
+                    'name' => 'my-function',
+                ],
+                [
+                    'specification' => 's-1vcpu-512mb',
+                    'name' => 'my-function',
+                ]
+            ],
+            'handle missing buildSpecification' => [
+                [
+                    'deploymentRetention' => 0,
+                    'name' => 'my-function',
+                ],
+                [
+                    'specification' => null,
+                    'name' => 'my-function',
+                ]
+            ],
+        ];
+    }
+
+    #[DataProvider('functionProvider')]
+    public function testFunction(array $content, array $expected): void
+    {
+        $model = Response::MODEL_FUNCTION;
+
+        $result = $this->filter->parse($content, $model);
+
+        $this->assertEquals($expected, $result);
+    }
+
+    public static function functionListProvider(): array
+    {
+        return [
+            'convert list of functions' => [
+                [
+                    'total' => 2,
+                    'functions' => [
+                        [
+                            'buildSpecification' => 's-1vcpu-512mb',
+                            'runtimeSpecification' => 's-1vcpu-512mb',
+                            'deploymentRetention' => 7,
+                            'name' => 'function-1',
+                        ],
+                        [
+                            'buildSpecification' => 's-2vcpu-1gb',
+                            'runtimeSpecification' => 's-1vcpu-512mb',
+                            'deploymentRetention' => 0,
+                            'name' => 'function-2',
+                        ],
+                    ],
+                ],
+                [
+                    'total' => 2,
+                    'functions' => [
+                        [
+                            'specification' => 's-1vcpu-512mb',
+                            'name' => 'function-1',
+                        ],
+                        [
+                            'specification' => 's-2vcpu-1gb',
+                            'name' => 'function-2',
+                        ],
+                    ],
+                ]
+            ],
+        ];
+    }
+
+    #[DataProvider('functionListProvider')]
+    public function testFunctionList(array $content, array $expected): void
+    {
+        $model = Response::MODEL_FUNCTION_LIST;
+
+        $result = $this->filter->parse($content, $model);
+
+        $this->assertEquals($expected, $result);
+    }
+
+    public static function siteProvider(): array
+    {
+        return [
+            'convert buildSpecification to specification and remove new fields' => [
+                [
+                    'buildSpecification' => 's-1vcpu-512mb',
+                    'runtimeSpecification' => 's-1vcpu-512mb',
+                    'deploymentRetention' => 7,
+                    'startCommand' => 'node custom-server.js',
+                    'name' => 'my-site',
+                ],
+                [
+                    'specification' => 's-1vcpu-512mb',
+                    'name' => 'my-site',
+                ]
+            ],
+            'handle missing buildSpecification' => [
+                [
+                    'deploymentRetention' => 0,
+                    'startCommand' => '',
+                    'name' => 'my-site',
+                ],
+                [
+                    'specification' => null,
+                    'name' => 'my-site',
+                ]
+            ],
+        ];
+    }
+
+    #[DataProvider('siteProvider')]
+    public function testSite(array $content, array $expected): void
+    {
+        $model = Response::MODEL_SITE;
+
+        $result = $this->filter->parse($content, $model);
+
+        $this->assertEquals($expected, $result);
+    }
+
+    public static function siteListProvider(): array
+    {
+        return [
+            'convert list of sites' => [
+                [
+                    'total' => 1,
+                    'sites' => [
+                        [
+                            'buildSpecification' => 's-1vcpu-512mb',
+                            'runtimeSpecification' => 's-1vcpu-512mb',
+                            'deploymentRetention' => 7,
+                            'startCommand' => 'node custom-server.js',
+                            'name' => 'site-1',
+                        ],
+                    ],
+                ],
+                [
+                    'total' => 1,
+                    'sites' => [
+                        [
+                            'specification' => 's-1vcpu-512mb',
+                            'name' => 'site-1',
+                        ],
+                    ],
+                ]
+            ],
+        ];
+    }
+
+    #[DataProvider('siteListProvider')]
+    public function testSiteList(array $content, array $expected): void
+    {
+        $model = Response::MODEL_SITE_LIST;
+
+        $result = $this->filter->parse($content, $model);
+
+        $this->assertEquals($expected, $result);
+    }
+}