diff --git a/.github/workflows/backend.yml b/.github/workflows/backend.yml
index 78c7b9b..2f9fd17 100644
--- a/.github/workflows/backend.yml
+++ b/.github/workflows/backend.yml
@@ -8,5 +8,6 @@ jobs:
     with:
       enable_backend_testing: true
       enable_phpstan: true
+      php_versions: '["7.4", "8.0, "8.1", "8.2", "8.3"]'
 
       backend_directory: .
diff --git a/composer.json b/composer.json
index 0c9e698..39e79aa 100644
--- a/composer.json
+++ b/composer.json
@@ -28,6 +28,7 @@
         }
     ],
     "require": {
+        "php": "^7.4 || ^8.0",
         "flarum/core": "^1.8.1",
         "league/oauth1-client": "^1.10.1",
         "league/oauth2-facebook": "^2.2.0",
@@ -71,7 +72,10 @@
                 "name": "fas fa-sign-in-alt",
                 "backgroundColor": "#e74c3c",
                 "color": "#fff"
-            }
+            },
+            "optional-dependencies": [
+                "flarum/gdpr"
+            ]
         },
         "flagrow": {
             "discuss": "https://discuss.flarum.org/d/25182"
diff --git a/extend.php b/extend.php
index c16aca0..caaa245 100644
--- a/extend.php
+++ b/extend.php
@@ -80,4 +80,12 @@
 
     (new Extend\SimpleFlarumSearch(UserSearcher::class))
         ->addGambit(Query\SsoIdFilterGambit::class),
+
+    (new Extend\Conditional())
+        ->whenExtensionEnabled('flarum-gdpr', fn () => [
+            (new Extend\ApiSerializer(ForumSerializer::class))
+                ->attribute('passwordlessSignUp', function (ForumSerializer $serializer) {
+                    return !$serializer->getActor()->isGuest() && $serializer->getActor()->loginProviders()->count() > 0;
+                }),
+        ]),
 ];