diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 31486ba..068c754 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,10 +3,6 @@ name: PHP CI
 on:
     schedule:
         - cron: '5 16 * * 3'
-    push:
-        paths-ignore:
-            - '**.md'
-            - LICENSE
     pull_request:
         paths-ignore:
             - '**.md'
@@ -17,6 +13,47 @@ permissions:
     pull-requests: read
 
 jobs:
+    validator-compatibility:
+        name: Symfony Validator ${{ matrix.validator }} / PHP 8.4
+        runs-on: ubuntu-latest
+        strategy:
+            fail-fast: false
+            matrix:
+                validator: ['5.4', '6.4', '7.4']
+        env:
+            SYMFONY_VALIDATOR_VERSION: ${{ matrix.validator }}
+        steps:
+            - name: Checkout code
+              uses: actions/checkout@v7
+
+            - name: Set up PHP 8.4
+              uses: shivammathur/setup-php@v2
+              with:
+                  php-version: '8.4'
+                  coverage: pcov
+                  tools: composer:v2
+                  extensions: mbstring
+
+            - name: Install the selected Symfony Validator version
+              run: composer update --with "symfony/validator:${SYMFONY_VALIDATOR_VERSION}.*" --prefer-dist --no-interaction
+
+            - name: Verify the installed Symfony Validator version
+              run: |
+                  composer show symfony/validator
+                  php <<'PHP'
+                  <?php
+                  require 'vendor/autoload.php';
+                  $version = Composer\InstalledVersions::getPrettyVersion('symfony/validator');
+                  $expected = getenv('SYMFONY_VALIDATOR_VERSION');
+                  if (1 !== preg_match('/^v?'.preg_quote($expected, '/').'\./', $version ?? '')) {
+                      fwrite(STDERR, "Expected Symfony Validator $expected.x, installed $version\n");
+                      exit(1);
+                  }
+                  PHP
+
+            - name: Run the complete test suite
+              run: composer test
+
     stable-build:
         name: PHP 8.4
         runs-on: ubuntu-latest
diff --git a/composer.json b/composer.json
index dc561b7..c08e37a 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,7 @@
         "longitude-one/geo-parser": "^4.1",
         "longitude-one/spatial-core": "^1.3",
         "doctrine/deprecations": "^1.1.3",
-        "symfony/validator": "^8.1"
+        "symfony/validator": "^5.4 || ^6.0 || ^7.0 || ^8.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^13",
diff --git a/docs/validators.md b/docs/validators.md
index d9ca5d6..2f6deb4 100644
--- a/docs/validators.md
+++ b/docs/validators.md
@@ -1,5 +1,11 @@
 # Spatial validators
 
+Symfony Validator `^5.4 || ^6.0 || ^7.0 || ^8.0` is supported. Versions below
+5.4 and future major versions such as 9.x are not accepted. The library still
+requires PHP 8.4 or later within PHP 8.x, independently of Symfony's requirements.
+CI explicitly installs and verifies Validator 5.4.x, 6.4.x, 7.4.x and 8.1.x,
+then runs the complete test suite for each version.
+
 This library exposes Symfony Validator constraints for checking spatial values.
 They are useful in two complementary situations:
 
diff --git a/tests/README.md b/tests/README.md
index 1b719b1..af9afc1 100644
--- a/tests/README.md
+++ b/tests/README.md
@@ -1,9 +1,9 @@
-## Tests
+# Tests
 
 The `Unit` directory contains the unit tests of the spatial types extension.
 The `Functional` directory contains functional tests.
 
-### Running the tests
+## Running the tests
 
 To run the tests, you need to install the dependencies using composer:
 
@@ -17,9 +17,21 @@ Then, run the following command:
 $ composer test
 ```
 
-If you use the docker environment, you can run the following commands:
+### Symfony Validator compatibility
+
+CI runs the complete `composer test` suite with Symfony Validator 5.4.x,
+6.4.x, 7.4.x and 8.1.x on PHP 8.4, in addition to the existing PHP 8.4 and
+8.5 jobs. Each compatibility job forces its selected minor version and verifies
+the installed version before running the tests.
+
+To reproduce a compatibility run locally, use a temporary Composer constraint
+(replace `5.4.*` with `6.4.*`, `7.4.*` or `8.1.*` for the other versions):
 
 ```bash
-$ docker compose exec si-php8 composer install
-$ docker compose exec si-php8 composer test
+composer update --with 'symfony/validator:5.4.*' --prefer-dist --no-interaction
+composer show symfony/validator
+composer test
 ```
+
+This does not change the supported range in `composer.json`. Run `composer update`
+without the temporary constraint to return to the default dependency resolution.