Document PHP 8.3 and PHPUnit 12.5 upgrade requirements in UPGRADE-2.3.md and CHANGELOG-2.3.md

CHANGELOG-2.3.md

@@ -0,0 +1,7 @@
+# CHANGELOG FOR `2.3.X`
+
+## v2.3.0 (unreleased)
+
+#### Details
+
+- [#19034](https://github.com/Sylius/Sylius/pull/19034) Upgrade PHP requirement to `^8.3` and PHPUnit to `^12.5` ([@tomkalon](https://github.com/tomkalon))

UPGRADE-2.3.md

@@ -54,7 +54,32 @@
 
    The `StringInflector::nameToSlug()` method has been **deprecated** and will be removed in Sylius 3.0.
 
-2. The `knplabs/gaufrette` and `knplabs/knp-gaufrette-bundle` packages have been removed.
+2. The minimum required **PHP version** has been raised from `^8.2` to `^8.3`. ([#19034](https://github.com/Sylius/Sylius/pull/19034))
+
+   Ensure your environment runs PHP 8.3 or higher before upgrading.
+
+3. The minimum required **PHPUnit version** has been raised from `^11.5` to `^12.5`. ([#19034](https://github.com/Sylius/Sylius/pull/19034))
+
+   If you have custom test suites extending Sylius test infrastructure, review the [PHPUnit 12 migration guide](https://docs.phpunit.de/en/12.0/migration-guide.html) for breaking changes. The key changes are:
+   - PHPDoc annotations (`@dataProvider`, `@test`, `@depends`) are no longer supported — use PHP attributes (`#[DataProvider]`, `#[Test]`, `#[Depends]`) instead.
+   - `MockBuilder::addMethods()` has been removed — use anonymous classes or interfaces instead.
+   - `createMock()` without expectations now triggers a PHPUnit notice — add the `#[AllowMockObjectsWithoutExpectations]` attribute to your test class to suppress it.
+   - `tests/Api/JsonApiTestCase.php` initialization has been moved from the constructor to `setUp()`. If you extend this class and override `__construct()`, migrate your initialization to `setUp()`:
+
+     ```diff
+     -public function __construct(?string $name = null, array $data = [], int|string $dataName = '')
+     -{
+     -    parent::__construct($name, $data, $dataName);
+     -    // your initialization
+     -}
+     +protected function setUp(): void
+     +{
+     +    parent::setUp();
+     +    // your initialization
+     +}
+     ```
+
+4. The `knplabs/gaufrette` and `knplabs/knp-gaufrette-bundle` packages have been removed.
 
    The Gaufrette integration has been unusable as a filesystem adapter.
    Since Sylius 2.0 the default filesystem adapter uses Flysystem instead.