diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 89093a7..4582b95 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -55,8 +55,8 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
-          # Pin ext-mongodb to a 1.20+ line compatible with mongodb/mongodb ^1.20
-          extensions: pdo, pdo_mysql, pdo_sqlite, pdo_pgsql, mongodb-1.20.1
+          # Pin ext-mongodb to a 1.21+ line compatible with mongodb/mongodb ^1.20 (which resolves to 1.21+)
+          extensions: pdo, pdo_mysql, pdo_sqlite, pdo_pgsql, mongodb-1.21.0
           coverage: none
 
       - name: Install dependencies
diff --git a/README.md b/README.md
index 11bf5a9..bb73588 100644
--- a/README.md
+++ b/README.md
@@ -30,7 +30,7 @@ composer install
 vendor/bin/phpunit
 ```
 
-- **Run MongoDB integration tests** (requires `ext-mongodb >= 1.20` and a reachable server):
+- **Run MongoDB integration tests** (requires `ext-mongodb >= 1.21` and a reachable server):
 ```bash
 MONGO_HOST=127.0.0.1 MONGO_PORT=27017 vendor/bin/phpunit --group mongo-integration
 ```
diff --git a/composer.json b/composer.json
index 1d1aa59..5a62958 100644
--- a/composer.json
+++ b/composer.json
@@ -39,8 +39,8 @@
   },
   "require": {
     "php": "^8.2",
-    "ext-mongodb": "^1.20",
-    "mongodb/mongodb": "^1.20",
+    "ext-mongodb": "^1.21",
+    "mongodb/mongodb": "^1.21",
     "psr/simple-cache": "^3.0"
   },
   "autoload": {
diff --git a/composer.lock b/composer.lock
index a5d4692..0f6dd94 100644
--- a/composer.lock
+++ b/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": "11f93ad2569b5071bfe47d842a4fa8da",
+    "content-hash": "4b460634f481dac571848ddf91d287ae",
     "packages": [
         {
             "name": "mongodb/mongodb",
@@ -1862,7 +1862,7 @@
     "prefer-lowest": false,
     "platform": {
         "php": "^8.2",
-        "ext-mongodb": "^1.20"
+        "ext-mongodb": "^1.21"
     },
     "platform-dev": {},
     "plugin-api-version": "2.6.0"