diff --git a/.github/workflows/build_scoped_rector.yaml b/.github/workflows/build_scoped_rector.yaml
index 80d1624af84..30b96573a43 100644
--- a/.github/workflows/build_scoped_rector.yaml
+++ b/.github/workflows/build_scoped_rector.yaml
@@ -38,7 +38,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
                 # fixes https://github.com/rectorphp/rector/pull/4559/checks?check_run_id=1359814403, see https://github.com/shivammathur/setup-php#composer-github-oauth
diff --git a/.github/workflows/claude_issue_fixer.yaml b/.github/workflows/claude_issue_fixer.yaml
index 6212c6e7e7b..7c4d42d759b 100644
--- a/.github/workflows/claude_issue_fixer.yaml
+++ b/.github/workflows/claude_issue_fixer.yaml
@@ -30,7 +30,7 @@ jobs:
             - name: Set up PHP
               uses: shivammathur/setup-php@v2
               with:
-                  php-version: '8.3'
+                  php-version: '8.4'
                   tools: composer:v2
                   coverage: none
 
diff --git a/.github/workflows/code_analysis.yaml b/.github/workflows/code_analysis.yaml
index 1670042a6bc..cc7683329cc 100644
--- a/.github/workflows/code_analysis.yaml
+++ b/.github/workflows/code_analysis.yaml
@@ -92,7 +92,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
             -   uses: "ramsey/composer-install@v4"
diff --git a/.github/workflows/code_analysis_no_dev.yaml b/.github/workflows/code_analysis_no_dev.yaml
index 19bb5787803..532a6136ebb 100644
--- a/.github/workflows/code_analysis_no_dev.yaml
+++ b/.github/workflows/code_analysis_no_dev.yaml
@@ -17,7 +17,7 @@ jobs:
             # see https://github.com/shivammathur/setup-php
             -   uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
             -  run: |
diff --git a/.github/workflows/e2e.yaml b/.github/workflows/e2e.yaml
index be970e32f7d..4456fd36529 100644
--- a/.github/workflows/e2e.yaml
+++ b/.github/workflows/e2e.yaml
@@ -22,7 +22,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php_version: ['8.3']
+                php_version: ['8.4']
                 directory:
                     - 'e2e/applied-auto-import'
                     - 'e2e/applied-polyfill-php80'
diff --git a/.github/workflows/e2e_command_with_option.yaml b/.github/workflows/e2e_command_with_option.yaml
index e0edf1fcb7c..349f4281fba 100644
--- a/.github/workflows/e2e_command_with_option.yaml
+++ b/.github/workflows/e2e_command_with_option.yaml
@@ -27,7 +27,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
             -   uses: "ramsey/composer-install@v4"
diff --git a/.github/workflows/e2e_with_cache.yaml b/.github/workflows/e2e_with_cache.yaml
index 97b6062b6a4..6c6f9daa675 100644
--- a/.github/workflows/e2e_with_cache.yaml
+++ b/.github/workflows/e2e_with_cache.yaml
@@ -22,7 +22,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php_version: ['8.3']
+                php_version: ['8.4']
                 directory:
                     - 'e2e/applied-rule-removed-node-with-cache'
                     - 'e2e/timeout-file-not-cached'
@@ -64,7 +64,7 @@ jobs:
 
             -   uses: shivammathur/setup-php@v2
                 with:
-                    php-version: '8.3'
+                    php-version: '8.4'
                     coverage: none
 
             -   run: composer install --ansi
diff --git a/.github/workflows/e2e_with_no_diffs.yaml b/.github/workflows/e2e_with_no_diffs.yaml
index d44364b203c..e3af82a4d91 100644
--- a/.github/workflows/e2e_with_no_diffs.yaml
+++ b/.github/workflows/e2e_with_no_diffs.yaml
@@ -22,7 +22,7 @@ jobs:
         strategy:
             fail-fast: false
             matrix:
-                php_version: ['8.3']
+                php_version: ['8.4']
                 directory:
                     - 'e2e/applied-rule-removed-node-no-diffs'
                     - 'e2e/applied-no-diffs-format-json'
diff --git a/.github/workflows/packages_tests.yaml b/.github/workflows/packages_tests.yaml
index ea071e6befe..0f910c4c15e 100644
--- a/.github/workflows/packages_tests.yaml
+++ b/.github/workflows/packages_tests.yaml
@@ -45,7 +45,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
             -   run: composer config minimum-stability dev
diff --git a/.github/workflows/phpstan_printer_test.yaml b/.github/workflows/phpstan_printer_test.yaml
index 49e5e16d8fb..e40208db989 100644
--- a/.github/workflows/phpstan_printer_test.yaml
+++ b/.github/workflows/phpstan_printer_test.yaml
@@ -18,7 +18,7 @@ jobs:
             fail-fast: false
             matrix:
                 os: [ubuntu-latest, windows-latest]
-                php-versions: ['8.3']
+                php-versions: ['8.4']
 
         runs-on: ${{ matrix.os }}
         timeout-minutes: 3
diff --git a/.github/workflows/phpunit_and_phpstan_autoload_compat_test.yaml b/.github/workflows/phpunit_and_phpstan_autoload_compat_test.yaml
index 85f737b3bfc..b5effabcc0e 100644
--- a/.github/workflows/phpunit_and_phpstan_autoload_compat_test.yaml
+++ b/.github/workflows/phpunit_and_phpstan_autoload_compat_test.yaml
@@ -19,15 +19,15 @@ jobs:
                     -
                         name: 'Rector dev + PHPUnit 10'
                         run: composer require "phpunit/phpunit:10.*" -W
-                        php: 8.2
+                        php: 8.4
                     -
                         name: 'Rector dev + PHPUnit 11'
                         run: composer require "phpunit/phpunit:11.*" -W
-                        php: 8.2
+                        php: 8.4
                     -
                         name: 'Rector dev + PHPUnit 12'
                         run: composer require "phpunit/phpunit:12.*" -W
-                        php: 8.3
+                        php: 8.4
 
         name: ${{ matrix.actions.name }}
 
diff --git a/.github/workflows/rector.yaml b/.github/workflows/rector.yaml
index 743cb3ebc33..8cfd1220882 100644
--- a/.github/workflows/rector.yaml
+++ b/.github/workflows/rector.yaml
@@ -24,8 +24,8 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    # PHP 8.3 is required, so Rector's code is PHP 8.3 compatible even after refactoring
-                    php-version: 8.3
+                    # PHP 8.4 is required, so Rector's code is PHP 8.4 compatible even after refactoring
+                    php-version: 8.4
                     coverage: none
 
             -   run: composer install --no-progress --ansi
diff --git a/.github/workflows/rector_drupal_rector_dev.yaml b/.github/workflows/rector_drupal_rector_dev.yaml
index 2be25002392..39b24b9354b 100644
--- a/.github/workflows/rector_drupal_rector_dev.yaml
+++ b/.github/workflows/rector_drupal_rector_dev.yaml
@@ -18,7 +18,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
                 # fixes https://github.com/rectorphp/rector/pull/4559/checks?check_run_id=1359814403, see https://github.com/shivammathur/setup-php#composer-github-oauth
diff --git a/.github/workflows/rector_laravel_rector_dev.yaml b/.github/workflows/rector_laravel_rector_dev.yaml
index ad80c419076..9d0304c5ced 100644
--- a/.github/workflows/rector_laravel_rector_dev.yaml
+++ b/.github/workflows/rector_laravel_rector_dev.yaml
@@ -18,7 +18,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
                 # fixes https://github.com/rectorphp/rector/pull/4559/checks?check_run_id=1359814403, see https://github.com/shivammathur/setup-php#composer-github-oauth
diff --git a/.github/workflows/remove_unused_deps.yaml b/.github/workflows/remove_unused_deps.yaml
index b5e50383456..0578eeeefe3 100644
--- a/.github/workflows/remove_unused_deps.yaml
+++ b/.github/workflows/remove_unused_deps.yaml
@@ -22,7 +22,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
             -   run: composer install --no-progress --ansi
diff --git a/.github/workflows/tests.yaml b/.github/workflows/tests.yaml
index 0b189cfa00b..5335d442d7c 100644
--- a/.github/workflows/tests.yaml
+++ b/.github/workflows/tests.yaml
@@ -18,7 +18,7 @@ jobs:
             fail-fast: false
             matrix:
                 os: [ubuntu-latest, windows-latest]
-                php-versions: ['8.3', '8.4', '8.5']
+                php-versions: ['8.4', '8.5']
 
         runs-on: ${{ matrix.os }}
         timeout-minutes: 4
diff --git a/.github/workflows/weekly_pull_requests.yaml b/.github/workflows/weekly_pull_requests.yaml
index 01f59d89fb2..2f9bdadd3b0 100644
--- a/.github/workflows/weekly_pull_requests.yaml
+++ b/.github/workflows/weekly_pull_requests.yaml
@@ -41,7 +41,7 @@ jobs:
             -
                 uses: shivammathur/setup-php@v2
                 with:
-                    php-version: 8.3
+                    php-version: 8.4
                     coverage: none
 
             -   uses: "ramsey/composer-install@v4"
diff --git a/build/build-preload.php b/build/build-preload.php
index e35185370f8..80a2e084ffc 100755
--- a/build/build-preload.php
+++ b/build/build-preload.php
@@ -216,7 +216,7 @@ private function buildPreloadScriptPhpParser(string $buildDirectory, string $pre
      */
     private function findPhpParserFiles(string $vendorDir): array
     {
-        $finder = (new Finder())
+        $finder = new Finder()
             ->files()
             ->name('*.php')
             ->in($vendorDir . '/nikic/php-parser/lib/PhpParser')
@@ -233,7 +233,7 @@ private function findPhpParserFiles(string $vendorDir): array
      */
     private function findPhpDocParserFiles(string $vendorDir): array
     {
-        $finder = (new Finder())
+        $finder = new Finder()
             ->files()
             ->name('*.php')
             ->in($vendorDir . '/phpstan/phpdoc-parser')
diff --git a/composer.json b/composer.json
index 696ea08853f..f63e938be50 100644
--- a/composer.json
+++ b/composer.json
@@ -12,7 +12,7 @@
         "migration"
     ],
     "require": {
-        "php": "^8.3",
+        "php": "^8.4",
         "clue/ndjson-react": "^1.3",
         "composer/pcre": "^3.4.0",
         "composer/semver": "^3.4",
@@ -36,7 +36,6 @@
         "symfony/console": "^6.4.24",
         "symfony/filesystem": "^7.4",
         "symfony/finder": "^6.4",
-        "symfony/polyfill-php84": "^1.38",
         "symfony/process": "^7.4",
         "symplify/easy-parallel": "^11.2.2",
         "symplify/rule-doc-generator-contracts": "^11.2",
@@ -51,14 +50,12 @@
         "phpstan/phpstan-phpunit": "^2.0",
         "phpstan/phpstan-webmozart-assert": "^2.0",
         "phpunit/phpunit": "^12.5.6",
-        "rector/jack": "^0.5",
-        "rector/release-notes-generator": "^0.5.1",
+        "rector/jack": "^1.0",
         "rector/swiss-knife": "^2.4.1",
         "rector/type-perfect": "^2.1.2",
         "shipmonk/composer-dependency-analyser": "^1.8",
-        "symplify/easy-coding-standard": "^13.1",
-        "symplify/phpstan-extensions": "^12.0.2",
-        "symplify/phpstan-rules": "^14.9.11",
+        "symplify/easy-coding-standard": "^13.2",
+        "symplify/phpstan-rules": "^14.12",
         "symplify/vendor-patches": "^11.5",
         "tomasvotruba/class-leak": "^2.1",
         "tomasvotruba/unused-public": "^2.2",
@@ -118,8 +115,7 @@
         "fix-cs": "vendor/bin/ecs check --fix --ansi",
         "phpstan": "vendor/bin/phpstan analyse --ansi --memory-limit=512M",
         "rector": "bin/rector process --ansi",
-        "preload": "php build/build-preload.php .",
-        "release": "vendor/bin/rng --from-commit X --to-commit Y --remote-repository rectorphp/rector-symfony --remote-repository rectorphp/rector-doctrine --remote-repository rectorphp/rector-phpunit"
+        "preload": "php build/build-preload.php ."
     },
     "extra": {
         "patches": {
diff --git a/config/config.php b/config/config.php
index fa62bbed1f5..b1afe8533af 100644
--- a/config/config.php
+++ b/config/config.php
@@ -29,7 +29,7 @@
 
     // use faster in-memory cache in CI.
     // CI always starts from scratch, therefore IO intensive caching is not worth it
-    if ((new CiDetector())->isCiDetected()) {
+    if (new CiDetector()->isCiDetected()) {
         $rectorConfig->cacheClass(MemoryCacheStorage::class);
     }
 
diff --git a/phpstan.neon b/phpstan.neon
index 6585a348409..efd9a79a4cc 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -25,6 +25,13 @@ parameters:
     checkMissingCallableSignature: true
     treatPhpDocTypesAsCertain: false
 
+    # see https://github.com/symplify/phpstan-rules
+    symplify:
+        symfonyReturnType: true
+        laravelReturnType: true
+        pathStrings: true
+        ctor: true
+
     paths:
         - rector.php
         - bin
@@ -344,12 +351,9 @@ parameters:
         # list vs array
         - '#Parameter (.*?) expects list<(.*?)>, array<(.*?)> given#'
 
-        - identifier: symplify.noConstructorOverride
-          path: src/StaticTypeMapper/ValueObject/Type/SimpleStaticType.php
-
         -
-            identifier: arrayValues.list
-            path: rules/CodingStyle/Application/UseImportsAdder.php
+            identifier: symplify.noConstructorOverride
+            path: src/StaticTypeMapper/ValueObject/Type/SimpleStaticType.php
 
         -
             message: '#Offset float\|int\|string might not exist on string#'
@@ -449,12 +453,11 @@ parameters:
 
         - '#Provide more specific return type "Iterator|PhpParser\\Node" over abstract one#'
 
-        # BC layer
-        -
-            message: '#Access to deprecated property \$file of class Rector\\Rector\\AbstractRector#'
-            path: src/Rector/AbstractRector.php
-
         # allowed
         -
             message: '#"@\\simplexml_load_string\(\$junitXml\)" is forbidden to use#'
             path: scripts/remove-unused-deps.php
+
+        -
+            path: src/Util/Reflection/PrivatesAccessor.php
+            identifier: symplify.newOverSetters
diff --git a/rules/DeadCode/Rector/If_/RemoveTypedPropertyDeadInstanceOfRector.php b/rules/DeadCode/Rector/If_/RemoveTypedPropertyDeadInstanceOfRector.php
index 2a52fed02b9..29d919ea431 100644
--- a/rules/DeadCode/Rector/If_/RemoveTypedPropertyDeadInstanceOfRector.php
+++ b/rules/DeadCode/Rector/If_/RemoveTypedPropertyDeadInstanceOfRector.php
@@ -10,6 +10,7 @@
 use PhpParser\Node\Expr\PropertyFetch;
 use PhpParser\Node\Expr\StaticPropertyFetch;
 use PhpParser\Node\Name;
+use PhpParser\Node\Param;
 use PhpParser\Node\Stmt;
 use PhpParser\Node\Stmt\Class_;
 use PhpParser\Node\Stmt\Do_;
@@ -208,6 +209,6 @@ private function isInPropertyPromotedParams(Class_ $class, PropertyFetch|StaticP
         /** @var string $propertyName */
         $propertyName = $this->getName($propertyFetch);
         $params = $this->promotedPropertyResolver->resolveFromClass($class);
-        return array_any($params, fn (Node $param): bool => $this->isName($param, $propertyName));
+        return array_any($params, fn (Param $param): bool => $this->isName($param, $propertyName));
     }
 }
diff --git a/scripts/no-php-file-in-fixtures.php b/scripts/no-php-file-in-fixtures.php
index d363b557ff7..80d956a425d 100644
--- a/scripts/no-php-file-in-fixtures.php
+++ b/scripts/no-php-file-in-fixtures.php
@@ -72,7 +72,7 @@ private function findPhpFiles(array $directories): array
     {
         Assert::allDirectory($directories);
 
-        $finder = (new Finder())
+        $finder = new Finder()
             ->files()
             ->in($directories)
             ->path('/Fixture')
@@ -92,7 +92,7 @@ private function findFixtureFiles(array $directories): array
     {
         Assert::allDirectory($directories);
 
-        $finder = (new Finder())
+        $finder = new Finder()
             ->files()
             ->in($directories)
             ->path('Fixture')
diff --git a/src/Bootstrap/AutoloadFileParameterResolver.php b/src/Bootstrap/AutoloadFileParameterResolver.php
index 7aa2462e7c4..b760f4a9c44 100644
--- a/src/Bootstrap/AutoloadFileParameterResolver.php
+++ b/src/Bootstrap/AutoloadFileParameterResolver.php
@@ -27,7 +27,8 @@ public static function resolveFromArgv(array $argv): void
         // handles "--autoload-file path", "--autoload-file=path" and "-a path";
         // parallel workers receive the space-separated form, so all spellings must
         // normalize to the same value or main process and workers would disagree
-        $autoloadFile = (new ArgvInput($argv))->getParameterOption(['--autoload-file', '-a'], null);
+        $autoloadFile = new ArgvInput($argv)
+            ->getParameterOption(['--autoload-file', '-a'], null);
         if (! is_string($autoloadFile) || $autoloadFile === '') {
             return;
         }
diff --git a/src/Configuration/RectorConfigBuilder.php b/src/Configuration/RectorConfigBuilder.php
index 0fadacd0134..72fe8c644fb 100644
--- a/src/Configuration/RectorConfigBuilder.php
+++ b/src/Configuration/RectorConfigBuilder.php
@@ -438,7 +438,8 @@ public function withSkipPath(string $skipPath): self
      */
     public function withRootFiles(): self
     {
-        $rootPhpFilesFinder = (new Finder())->files()
+        $rootPhpFilesFinder = new Finder()
+            ->files()
             ->in(getcwd())
             ->depth(0)
             ->ignoreDotFiles(false)
diff --git a/src/PhpParser/Comparing/NodeComparator.php b/src/PhpParser/Comparing/NodeComparator.php
index d9d5323c149..5bfac3d4c76 100644
--- a/src/PhpParser/Comparing/NodeComparator.php
+++ b/src/PhpParser/Comparing/NodeComparator.php
@@ -65,7 +65,7 @@ public function isNodeEqual(Node $singleNode, array $availableNodes): bool
     {
         return array_any(
             $availableNodes,
-            fn (Node|array|null $availableNode): bool => $this->areNodesEqual($singleNode, $availableNode)
+            fn (Node $availableNode): bool => $this->areNodesEqual($singleNode, $availableNode)
         );
     }