diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3d1103373cb..811051df702 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -129,6 +129,7 @@ jobs:
           - "8.1"
           - "8.2"
           - "8.3"
+          - "8.4"
         count: ${{ fromJson(needs.chunk-matrix.outputs.count) }}
         chunk: ${{ fromJson(needs.chunk-matrix.outputs.chunks) }}
 
diff --git a/composer.json b/composer.json
index aed943f1dd5..602928094c4 100644
--- a/composer.json
+++ b/composer.json
@@ -15,7 +15,7 @@
         }
     ],
     "require": {
-        "php": "^7.4 || ~8.0.0 || ~8.1.0 || ~8.2.0 || ~8.3.0",
+        "php": "^7.4 || ~8.0.0 || ~8.1.0 || ~8.2.0 || ~8.3.0 || ~8.4.0",
         "ext-SimpleXML": "*",
         "ext-ctype": "*",
         "ext-dom": "*",
@@ -30,7 +30,7 @@
         "composer/xdebug-handler": "^2.0 || ^3.0",
         "dnoegel/php-xdg-base-dir": "^0.1.1",
         "felixfbecker/advanced-json-rpc": "^3.1",
-        "felixfbecker/language-server-protocol": "^1.5.2",
+        "felixfbecker/language-server-protocol": "^1.5.3",
         "fidry/cpu-core-counter": "^0.4.1 || ^0.5.1 || ^1.0.0",
         "netresearch/jsonmapper": "^1.0 || ^2.0 || ^3.0 || ^4.0",
         "nikic/php-parser": "^4.17",
@@ -47,7 +47,7 @@
     },
     "require-dev": {
         "ext-curl": "*",
-        "amphp/phpunit-util": "^2.0",
+        "amphp/phpunit-util": "^2.0.1",
         "bamarni/composer-bin-plugin": "^1.4",
         "brianium/paratest": "^6.9",
         "mockery/mockery": "^1.5",
diff --git a/tests/Internal/Codebase/InternalCallMapHandlerTest.php b/tests/Internal/Codebase/InternalCallMapHandlerTest.php
index e5f6320fba5..e852bf5d9bc 100644
--- a/tests/Internal/Codebase/InternalCallMapHandlerTest.php
+++ b/tests/Internal/Codebase/InternalCallMapHandlerTest.php
@@ -45,6 +45,7 @@
 use const PHP_MAJOR_VERSION;
 use const PHP_MINOR_VERSION;
 use const PHP_VERSION;
+use const PHP_VERSION_ID;
 
 /** @group callmap */
 class InternalCallMapHandlerTest extends TestCase
@@ -78,8 +79,8 @@ class InternalCallMapHandlerTest extends TestCase
         'array_multisort',
         'datefmt_create' => ['8.0'],
         'fiber::start',
-        'get_class' => ['8.3'],
-        'get_parent_class' => ['8.3'],
+        'get_class' => ['8.3', '8.4'],
+        'get_parent_class' => ['8.3', '8.4'],
         'imagefilledpolygon',
         'imagegd',
         'imagegd2',
@@ -97,7 +98,7 @@ class InternalCallMapHandlerTest extends TestCase
         'mailparse_msg_get_structure',
         'mailparse_msg_parse',
         'mailparse_stream_encode',
-        'mb_check_encoding' => ['8.1', '8.2', '8.3'],
+        'mb_check_encoding' => ['8.1', '8.2', '8.3', '8.4'],
         'memcached::cas', // memcached 3.2.0 has incorrect reflection
         'memcached::casbykey', // memcached 3.2.0 has incorrect reflection
         'oauth::fetch',
@@ -175,60 +176,60 @@ class InternalCallMapHandlerTest extends TestCase
      * @var array<int|string, string|list<string>>
      */
     private static array $ignoredReturnTypeOnlyFunctions = [
-        'appenditerator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'appenditerator::getiteratorindex' => ['8.1', '8.2', '8.3'],
-        'cachingiterator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'callbackfilteriterator::getinneriterator' => ['8.1', '8.2', '8.3'],
+        'appenditerator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'appenditerator::getiteratorindex' => ['8.1', '8.2', '8.3', '8.4'],
+        'cachingiterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'callbackfilteriterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
         'curl_multi_getcontent',
-        'datetime::add' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
-        'datetime::modify' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
-        'datetime::createfromformat' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
+        'datetime::add' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
+        'datetime::modify' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
+        'datetime::createfromformat' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
         'datetime::createfromimmutable' => ['8.1'],
         'datetime::createfrominterface',
-        'datetime::setdate' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
-        'datetime::setisodate' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
-        'datetime::settime' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
-        'datetime::settimestamp' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
-        'datetime::settimezone' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
-        'datetime::sub' => ['8.1', '8.2', '8.3'], // DateTime does not contain static
+        'datetime::setdate' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
+        'datetime::setisodate' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
+        'datetime::settime' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
+        'datetime::settimestamp' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
+        'datetime::settimezone' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
+        'datetime::sub' => ['8.1', '8.2', '8.3', '8.4'], // DateTime does not contain static
         'datetimeimmutable::createfrominterface',
         'fiber::getcurrent',
-        'filteriterator::getinneriterator' => ['8.1', '8.2', '8.3'],
+        'filteriterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
         'get_cfg_var', // Ignore array return type
-        'infiniteiterator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'iteratoriterator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'limititerator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'locale::getallvariants' => ['8.1', '8.2', '8.3'],
-        'locale::getkeywords' => ['8.1', '8.2', '8.3'],
-        'locale::getprimarylanguage' => ['8.1', '8.2', '8.3'],
-        'locale::getregion' => ['8.1', '8.2', '8.3'],
-        'locale::getscript' => ['8.1', '8.2', '8.3'],
-        'locale::parselocale' => ['8.1', '8.2', '8.3'],
-        'messageformatter::create' => ['8.1', '8.2', '8.3'],
-        'multipleiterator::current' => ['8.1', '8.2', '8.3'],
-        'mysqli::get_charset' => ['8.1', '8.2', '8.3'],
-        'mysqli_stmt::get_warnings' => ['8.1', '8.2', '8.3'],
+        'infiniteiterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'iteratoriterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'limititerator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'locale::getallvariants' => ['8.1', '8.2', '8.3', '8.4'],
+        'locale::getkeywords' => ['8.1', '8.2', '8.3', '8.4'],
+        'locale::getprimarylanguage' => ['8.1', '8.2', '8.3', '8.4'],
+        'locale::getregion' => ['8.1', '8.2', '8.3', '8.4'],
+        'locale::getscript' => ['8.1', '8.2', '8.3', '8.4'],
+        'locale::parselocale' => ['8.1', '8.2', '8.3', '8.4'],
+        'messageformatter::create' => ['8.1', '8.2', '8.3', '8.4'],
+        'multipleiterator::current' => ['8.1', '8.2', '8.3', '8.4'],
+        'mysqli::get_charset' => ['8.1', '8.2', '8.3', '8.4'],
+        'mysqli_stmt::get_warnings' => ['8.1', '8.2', '8.3', '8.4'],
         'mysqli_stmt_get_warnings',
         'mysqli_stmt_insert_id',
-        'norewinditerator::getinneriterator' => ['8.1', '8.2', '8.3'],
+        'norewinditerator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
         'passthru',
-        'recursivecachingiterator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'recursivecallbackfilteriterator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'recursivefilteriterator::getinneriterator' => ['8.1', '8.2', '8.3'],
-        'recursiveregexiterator::getinneriterator' => ['8.1', '8.2', '8.3'],
+        'recursivecachingiterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'recursivecallbackfilteriterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'recursivefilteriterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
+        'recursiveregexiterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
         'reflectionclass::getstaticproperties' => ['8.1', '8.2'],
-        'reflectionclass::newinstanceargs' => ['8.1', '8.2', '8.3'],
-        'reflectionfunction::getclosurescopeclass' => ['8.1', '8.2', '8.3'],
-        'reflectionfunction::getclosurethis' => ['8.1', '8.2', '8.3'],
-        'reflectionmethod::getclosurescopeclass' => ['8.1', '8.2', '8.3'],
-        'reflectionmethod::getclosurethis' => ['8.1', '8.2', '8.3'],
+        'reflectionclass::newinstanceargs' => ['8.1', '8.2', '8.3', '8.4'],
+        'reflectionfunction::getclosurescopeclass' => ['8.1', '8.2', '8.3', '8.4'],
+        'reflectionfunction::getclosurethis' => ['8.1', '8.2', '8.3', '8.4'],
+        'reflectionmethod::getclosurescopeclass' => ['8.1', '8.2', '8.3', '8.4'],
+        'reflectionmethod::getclosurethis' => ['8.1', '8.2', '8.3', '8.4'],
         'reflectionobject::getstaticproperties' => ['8.1', '8.2'],
-        'reflectionobject::newinstanceargs' => ['8.1', '8.2', '8.3'],
-        'regexiterator::getinneriterator' => ['8.1', '8.2', '8.3'],
+        'reflectionobject::newinstanceargs' => ['8.1', '8.2', '8.3', '8.4'],
+        'regexiterator::getinneriterator' => ['8.1', '8.2', '8.3', '8.4'],
         'register_shutdown_function' => ['8.0', '8.1'],
-        'splfileobject::fscanf' => ['8.1', '8.2', '8.3'],
-        'spltempfileobject::fscanf' => ['8.1', '8.2', '8.3'],
-        'xsltprocessor::transformtoxml' => ['8.1', '8.2', '8.3'],
+        'splfileobject::fscanf' => ['8.1', '8.2', '8.3', '8.4'],
+        'spltempfileobject::fscanf' => ['8.1', '8.2', '8.3', '8.4'],
+        'xsltprocessor::transformtoxml' => ['8.1', '8.2', '8.3', '8.4'],
     ];
 
     /**
@@ -519,7 +520,12 @@ private function getReflectionFunction(string $functionName): ?ReflectionFunctio
     {
         try {
             if (strpos($functionName, '::') !== false) {
-                return new ReflectionMethod($functionName);
+                if (PHP_VERSION_ID < 8_03_00) {
+                    [$className, , $methodName] = explode(':', $functionName, 3);
+                    return new ReflectionMethod($className, $methodName);
+                }
+
+                return ReflectionMethod::createFromMethodName($functionName);
             }
 
             /** @var callable-string $functionName */