diff --git a/backend/composer.json b/backend/composer.json
index ee592c305..7a2329afa 100644
--- a/backend/composer.json
+++ b/backend/composer.json
@@ -29,7 +29,7 @@
         "spatie/icalendar-generator": "^3.0",
         "spatie/laravel-data": "^4.15",
         "spatie/laravel-webhook-server": "^3.8",
-        "stripe/stripe-php": "^17.0",
+        "stripe/stripe-php": "^21.1",
         "symfony/http-client": "^7.4",
         "symfony/postmark-mailer": "^7.4"
     },
diff --git a/backend/composer.lock b/backend/composer.lock
index c8ef47cac..de7281eed 100644
--- a/backend/composer.lock
+++ b/backend/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "9b1666c301c02d12a833ad54c450b69c",
+    "content-hash": "e683fe00e601df4e6d830ad68d475fb8",
     "packages": [
         {
             "name": "aws/aws-crt-php",
@@ -6652,28 +6652,28 @@
         },
         {
             "name": "stripe/stripe-php",
-            "version": "v17.6.0",
+            "version": "v21.1.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/stripe/stripe-php.git",
-                "reference": "a6219df5df1324a0d3f1da25fb5e4b8a3307ea16"
+                "reference": "5f68d5a285d206a757ebbd9bf0e037759a61c379"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/stripe/stripe-php/zipball/a6219df5df1324a0d3f1da25fb5e4b8a3307ea16",
-                "reference": "a6219df5df1324a0d3f1da25fb5e4b8a3307ea16",
+                "url": "https://api.github.com/repos/stripe/stripe-php/zipball/5f68d5a285d206a757ebbd9bf0e037759a61c379",
+                "reference": "5f68d5a285d206a757ebbd9bf0e037759a61c379",
                 "shasum": ""
             },
             "require": {
                 "ext-curl": "*",
                 "ext-json": "*",
                 "ext-mbstring": "*",
-                "php": ">=5.6.0"
+                "php": ">=7.2.0"
             },
             "require-dev": {
-                "friendsofphp/php-cs-fixer": "3.72.0",
+                "friendsofphp/php-cs-fixer": "3.94.0",
                 "phpstan/phpstan": "^1.2",
-                "phpunit/phpunit": "^5.7 || ^9.0"
+                "phpunit/phpunit": "^8.0 || ^9.0"
             },
             "type": "library",
             "extra": {
@@ -6682,6 +6682,9 @@
                 }
             },
             "autoload": {
+                "files": [
+                    "lib/version_check.php"
+                ],
                 "psr-4": {
                     "Stripe\\": "lib/"
                 }
@@ -6705,9 +6708,9 @@
             ],
             "support": {
                 "issues": "https://github.com/stripe/stripe-php/issues",
-                "source": "https://github.com/stripe/stripe-php/tree/v17.6.0"
+                "source": "https://github.com/stripe/stripe-php/tree/v21.1.1"
             },
-            "time": "2025-08-27T19:32:42+00:00"
+            "time": "2026-07-30T18:43:28+00:00"
         },
         {
             "name": "symfony/clock",