diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ac25f8c..1643321 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,14 +1,65 @@
 name: CI
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
-  build-test:
+  tests:
+    name: PHP ${{ matrix.php }} (${{ matrix.dependencies }}${{ matrix.dbal && ', dbal ' || '' }}${{ matrix.dbal }})
     runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        php: ['8.2', '8.3', '8.4', '8.5']
+        dependencies: [highest, lowest]
+        include:
+          - php: '8.2'
+            dependencies: highest
+            dbal: '^3.0'
+          - php: '8.4'
+            dependencies: highest
+            dbal: '^4.0'
 
     steps:
       - uses: actions/checkout@v6
-      - uses: php-actions/composer@v6 # or alternative dependency management
-      - uses: php-actions/phpunit@v4
-      - name: Run PHP CS Fixer
-        run: php vendor/bin/php-cs-fixer fix --dry-run --diff
\ No newline at end of file
+      - uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          coverage: none
+          tools: composer
+      - name: Pin doctrine/dbal
+        if: matrix.dbal
+        run: composer require --no-update "doctrine/dbal:${{ matrix.dbal }}"
+      - name: Install dependencies
+        run: composer update --no-interaction --no-progress --prefer-stable ${{ matrix.dependencies == 'lowest' && '--prefer-lowest' || '' }}
+      - name: Run PHPUnit
+        run: vendor/bin/phpunit
+
+  static-analysis:
+    name: Code style & static analysis
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.4'
+          coverage: none
+          tools: composer
+      - run: composer update --no-interaction --no-progress --prefer-stable
+      - name: PHP CS Fixer
+        run: vendor/bin/php-cs-fixer fix --dry-run --diff
+      - name: PHPStan
+        run: vendor/bin/phpstan analyse --no-progress
+
+  rector:
+    name: Rector
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v6
+      - uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.4'
+          coverage: none
+          tools: composer
+      - run: composer update --no-interaction --no-progress --prefer-stable
+      - name: Rector
+        run: vendor/bin/rector process --dry-run --no-progress-bar
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 679d424..5628010 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+# Version 6.0.4
+* Fix compatibility with `monolog/monolog` < 3.8 (`StreamHandler` `fileOpenMode` argument) in `JobProcessor`
+* Require `monolog/monolog` `^3.0` (`^2.0` was never installable with `symfony/monolog-bridge` 7.4)
+* Use the `#[Frequency]` attribute on `ScheduledDataflow::$frequency`
+* Fix PHPStan errors (`DateTimeInterface` clone in `ScheduledDataflowManager`, status types in `JobRepository`)
+* Add `league/flysystem` to dev dependencies
+* CI: test on PHP 8.2 to 8.5 with lowest and highest dependencies, and with `doctrine/dbal` 3 and 4; add PHPStan and Rector checks
+
 # Version 6.0.3
 * Fix job error count display using `Job::getExceptionCount()` when available in `JobShowCommand`
 * Fix exceptions retrieval when only a stream is available in `JobShowCommand`
diff --git a/composer.json b/composer.json
index 350d0b9..3dcbba6 100644
--- a/composer.json
+++ b/composer.json
@@ -45,7 +45,7 @@
         "ext-json": "*",
         "doctrine/dbal": "^3.0||^4.0",
         "doctrine/doctrine-bundle": "^2.0",
-        "monolog/monolog": "^2.0||^3.0",
+        "monolog/monolog": "^3.0",
         "psr/log": "^1.1||^2.0||^3.0",
         "symfony/config": "^7.4",
         "symfony/console": "^7.4",
@@ -62,6 +62,7 @@
         "amphp/amp": "^2.5",
         "ekino/phpstan-banned-code": "^3.2",
         "friendsofphp/php-cs-fixer": "^3.75",
+        "league/flysystem": "^3.0",
         "phpunit/phpunit": "^11",
         "portphp/portphp": "^1.9",
         "rector/rector": "^2.0",
diff --git a/rector.php b/rector.php
index 5beb0f7..0e2b1b7 100644
--- a/rector.php
+++ b/rector.php
@@ -15,7 +15,6 @@
     ->withSets([
         SymfonySetList::SYMFONY_CODE_QUALITY,
         SymfonySetList::SYMFONY_CONSTRUCTOR_INJECTION,
-        SymfonySetList::SYMFONY_73,
         LevelSetList::UP_TO_PHP_82,
     ])
 ;
diff --git a/src/Command/AddScheduledDataflowCommand.php b/src/Command/AddScheduledDataflowCommand.php
index fe20282..638fdf8 100644
--- a/src/Command/AddScheduledDataflowCommand.php
+++ b/src/Command/AddScheduledDataflowCommand.php
@@ -67,9 +67,7 @@ public function __invoke(
         if (!$firstRun) {
             $firstRun = $io->ask('When is the first execution of the scheduled dataflow (format: Y-m-d H:i:s)?');
         }
-        if ($enabled === null) {
-            $enabled = $io->confirm('Enable the scheduled dataflow?');
-        }
+        $enabled ??= $io->confirm('Enable the scheduled dataflow?');
 
         $newScheduledDataflow = ScheduledDataflow::createFromArray([
             'id' => null,
diff --git a/src/Command/ChangeScheduleStatusCommand.php b/src/Command/ChangeScheduleStatusCommand.php
index 2e665b4..93987a7 100644
--- a/src/Command/ChangeScheduleStatusCommand.php
+++ b/src/Command/ChangeScheduleStatusCommand.php
@@ -55,7 +55,7 @@ public function __invoke(
             return 3;
         }
 
-        $enable = $enable ?? !$disable;
+        $enable ??= !$disable;
 
         try {
             $schedule->setEnabled($enable);
diff --git a/src/Command/ExecuteDataflowCommand.php b/src/Command/ExecuteDataflowCommand.php
index 3a9c38c..d15a100 100644
--- a/src/Command/ExecuteDataflowCommand.php
+++ b/src/Command/ExecuteDataflowCommand.php
@@ -50,7 +50,7 @@ public function __invoke(
             $dataflowType->setRepository($this->jobRepository);
         }
 
-        if ($dataflowType instanceof LoggerAwareInterface && isset($this->logger)) {
+        if (isset($this->logger)) {
             $dataflowType->setLogger($this->logger);
         }
 
diff --git a/src/DataflowType/Dataflow/AMPAsyncDataflow.php b/src/DataflowType/Dataflow/AMPAsyncDataflow.php
index cdacac3..0801317 100644
--- a/src/DataflowType/Dataflow/AMPAsyncDataflow.php
+++ b/src/DataflowType/Dataflow/AMPAsyncDataflow.php
@@ -114,9 +114,7 @@ private function processState(mixed $state, int &$count, int &$countExceptions):
     {
         [$readIndex, $stepIndex, $item] = $state;
         if ($stepIndex < \count($this->steps)) {
-            if (!isset($this->stepsJobs[$stepIndex])) {
-                $this->stepsJobs[$stepIndex] = [];
-            }
+            $this->stepsJobs[$stepIndex] ??= [];
             [$step, $scale] = $this->steps[$stepIndex];
             if ((is_countable($this->stepsJobs[$stepIndex]) ? \count($this->stepsJobs[$stepIndex]) : 0) < $scale && !isset($this->stepsJobs[$stepIndex][$readIndex])) {
                 $this->stepsJobs[$stepIndex][$readIndex] = true;
diff --git a/src/DataflowType/Result.php b/src/DataflowType/Result.php
index 5a31ab6..f7ae9e9 100644
--- a/src/DataflowType/Result.php
+++ b/src/DataflowType/Result.php
@@ -11,7 +11,7 @@ class Result
 {
     private readonly \DateInterval $elapsed;
 
-    private int $successCount;
+    private readonly int $successCount;
 
     /** @var array<int, mixed> */
     private array $exceptions = [];
diff --git a/src/DependencyInjection/Configuration.php b/src/DependencyInjection/Configuration.php
index 9c21b1c..465d3c2 100644
--- a/src/DependencyInjection/Configuration.php
+++ b/src/DependencyInjection/Configuration.php
@@ -48,7 +48,7 @@ public function getConfigTreeBuilder(): TreeBuilder
                         ->end()
                     ->end()
                     ->validate()
-                        ->ifTrue(static fn ($v): bool => $v['type'] === 'file' && !class_exists('\League\Flysystem\Filesystem'))
+                        ->ifTrue(static fn ($v): bool => $v['type'] === 'file' && !class_exists(\League\Flysystem\Filesystem::class))
                         ->thenInvalid('You need "league/flysystem" to use Dataflow file exception mode.')
                     ->end()
                 ->end()
diff --git a/src/Entity/ScheduledDataflow.php b/src/Entity/ScheduledDataflow.php
index 161c806..43e6bcb 100644
--- a/src/Entity/ScheduledDataflow.php
+++ b/src/Entity/ScheduledDataflow.php
@@ -37,10 +37,8 @@ class ScheduledDataflow
 
     private ?array $options = null;
 
-    /**
-     * @Frequency()
-     */
     #[Asserts\NotBlank]
+    #[Frequency]
     private ?string $frequency = null;
 
     private ?\DateTimeInterface $next = null;
diff --git a/src/Manager/ScheduledDataflowManager.php b/src/Manager/ScheduledDataflowManager.php
index 3b5baa1..60abb60 100644
--- a/src/Manager/ScheduledDataflowManager.php
+++ b/src/Manager/ScheduledDataflowManager.php
@@ -41,7 +41,7 @@ public function createJobsFromScheduledDataflows(): void
     private function updateScheduledDataflowNext(ScheduledDataflow $scheduled): void
     {
         $interval = \DateInterval::createFromDateString($scheduled->getFrequency());
-        $next = clone $scheduled->getNext();
+        $next = \DateTime::createFromInterface($scheduled->getNext());
         $now = new \DateTime();
 
         while ($next < $now) {
diff --git a/src/Processor/JobProcessor.php b/src/Processor/JobProcessor.php
index 18f4d26..75fdf9b 100644
--- a/src/Processor/JobProcessor.php
+++ b/src/Processor/JobProcessor.php
@@ -46,7 +46,7 @@ public function process(Job $job): void
         }
 
         $tempFile = tempnam(sys_get_temp_dir(), 'dataflow_');
-        $handler = new StreamHandler($tempFile, fileOpenMode: 'w+');
+        $handler = new StreamHandler(fopen($tempFile, 'w+'));
         $handler->setFormatter(new LineFormatter(self::FORMAT));
 
         $loggers = [new Logger('dataflow_internal', [$bufferHandler = $handler])];
diff --git a/src/Repository/JobRepository.php b/src/Repository/JobRepository.php
index f96c17b..c3dc9f4 100644
--- a/src/Repository/JobRepository.php
+++ b/src/Repository/JobRepository.php
@@ -175,7 +175,7 @@ public function deleteOld(int $days): array
         $qb = $this->connection->createQueryBuilder();
         $ids = $qb->select('j.id')
             ->from(static::TABLE_NAME, 'j')
-            ->andWhere($qb->expr()->in('j.status', [Job::STATUS_COMPLETED, Job::STATUS_CRASHED]))
+            ->andWhere($qb->expr()->in('j.status', [(string) Job::STATUS_COMPLETED, (string) Job::STATUS_CRASHED]))
             ->andWhere('j.end_time < :date')
             ->setParameter('date', new \DateTime("- {$days} days"), 'datetime')
             ->executeQuery()
@@ -184,7 +184,7 @@ public function deleteOld(int $days): array
 
         $qb = $this->connection->createQueryBuilder();
         $qb->delete(static::TABLE_NAME.' j')
-            ->andWhere($qb->expr()->in('j.status', [Job::STATUS_COMPLETED, Job::STATUS_CRASHED]))
+            ->andWhere($qb->expr()->in('j.status', [(string) Job::STATUS_COMPLETED, (string) Job::STATUS_CRASHED]))
             ->andWhere('j.end_time < :date')
             ->setParameter('date', new \DateTime("- {$days} days"), 'datetime')
             ->executeStatement()
diff --git a/src/Validator/Constraints/Frequency.php b/src/Validator/Constraints/Frequency.php
index 231a3ef..9d7edcb 100644
--- a/src/Validator/Constraints/Frequency.php
+++ b/src/Validator/Constraints/Frequency.php
@@ -11,6 +11,7 @@
  *
  * @codeCoverageIgnore
  */
+#[\Attribute(\Attribute::TARGET_PROPERTY | \Attribute::TARGET_METHOD)]
 class Frequency extends Constraint
 {
     public $message = 'The provided frequency "{{ string }}" must be a valid parameter for DateInterval::createFromDateString() and must not represent a negative value';