diff --git a/.github/workflows/continuous-integration.yml b/.github/workflows/continuous-integration.yml
index 23adb9b8..5a760868 100644
--- a/.github/workflows/continuous-integration.yml
+++ b/.github/workflows/continuous-integration.yml
@@ -33,7 +33,7 @@ jobs:
           - php-version: "8.1"
             dependencies: lowest
             operating-system: ubuntu-latest
-          - php-version: "8.2"
+          - php-version: "8.4"
             dependencies: highest
             operating-system: ubuntu-latest
             composer-options: "--ignore-platform-req=php+"
@@ -50,7 +50,7 @@ jobs:
           couchdb version: '2.3.1'
 
       - name: Run MongoDB
-        uses: supercharge/mongodb-github-action@1.7.0
+        uses: supercharge/mongodb-github-action@1.10.0
         with:
           mongodb-version: 5.0
 
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index f5cbf9cc..0db61e04 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -17,6 +17,7 @@ jobs:
       matrix:
         php-version:
           - "8.1"
+          - "8.3"
 
     steps:
       - name: "Checkout"
diff --git a/.github/workflows/phpstan.yml b/.github/workflows/phpstan.yml
index a6a4e407..b3314065 100644
--- a/.github/workflows/phpstan.yml
+++ b/.github/workflows/phpstan.yml
@@ -37,7 +37,7 @@ jobs:
         run: echo "dir=$(composer config cache-files-dir)" >> "$GITHUB_OUTPUT"
 
       - name: Cache dependencies
-        uses: actions/cache@v3
+        uses: actions/cache@v4
         with:
           path: ${{ steps.composercache.outputs.dir }}
           key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
diff --git a/src/Monolog/DateTimeImmutable.php b/src/Monolog/DateTimeImmutable.php
index 274b73ea..3d9477f4 100644
--- a/src/Monolog/DateTimeImmutable.php
+++ b/src/Monolog/DateTimeImmutable.php
@@ -27,6 +27,8 @@ class DateTimeImmutable extends \DateTimeImmutable implements \JsonSerializable
     {
         $this->useMicroseconds = $useMicroseconds;
 
+        // if you like to use a custom time to pass to Logger::addRecord directly,
+        // call modify() or setTimestamp() on this instance to change the date after creating it
         parent::__construct('now', $timezone);
     }
 
diff --git a/src/Monolog/Handler/FilterHandler.php b/src/Monolog/Handler/FilterHandler.php
index 5fa558e1..66f65477 100644
--- a/src/Monolog/Handler/FilterHandler.php
+++ b/src/Monolog/Handler/FilterHandler.php
@@ -150,7 +150,7 @@ class FilterHandler extends Handler implements ProcessableHandlerInterface, Rese
      *
      * If the handler was provided as a factory, this will trigger the handler's instantiation.
      */
-    public function getHandler(LogRecord $record = null): HandlerInterface
+    public function getHandler(LogRecord|null $record = null): HandlerInterface
     {
         if (!$this->handler instanceof HandlerInterface) {
             $handler = ($this->handler)($record, $this);
diff --git a/src/Monolog/Handler/FingersCrossedHandler.php b/src/Monolog/Handler/FingersCrossedHandler.php
index 1c3df386..d4551fb9 100644
--- a/src/Monolog/Handler/FingersCrossedHandler.php
+++ b/src/Monolog/Handler/FingersCrossedHandler.php
@@ -199,7 +199,7 @@ class FingersCrossedHandler extends Handler implements ProcessableHandlerInterfa
      *
      * If the handler was provided as a factory, this will trigger the handler's instantiation.
      */
-    public function getHandler(LogRecord $record = null): HandlerInterface
+    public function getHandler(LogRecord|null $record = null): HandlerInterface
     {
         if (!$this->handler instanceof HandlerInterface) {
             $handler = ($this->handler)($record, $this);
diff --git a/src/Monolog/Handler/SamplingHandler.php b/src/Monolog/Handler/SamplingHandler.php
index 511ec585..db43d5a8 100644
--- a/src/Monolog/Handler/SamplingHandler.php
+++ b/src/Monolog/Handler/SamplingHandler.php
@@ -78,7 +78,7 @@ class SamplingHandler extends AbstractHandler implements ProcessableHandlerInter
      *
      * If the handler was provided as a factory, this will trigger the handler's instantiation.
      */
-    public function getHandler(LogRecord $record = null): HandlerInterface
+    public function getHandler(LogRecord|null $record = null): HandlerInterface
     {
         if (!$this->handler instanceof HandlerInterface) {
             $handler = ($this->handler)($record, $this);
diff --git a/src/Monolog/Handler/Slack/SlackRecord.php b/src/Monolog/Handler/Slack/SlackRecord.php
index 147d8f80..0cb8b9b4 100644
--- a/src/Monolog/Handler/Slack/SlackRecord.php
+++ b/src/Monolog/Handler/Slack/SlackRecord.php
@@ -86,7 +86,7 @@ class SlackRecord
         bool $useShortAttachment = false,
         bool $includeContextAndExtra = false,
         array $excludeFields = [],
-        FormatterInterface $formatter = null
+        FormatterInterface|null $formatter = null
     ) {
         $this
             ->setChannel($channel)
diff --git a/src/Monolog/Handler/TelegramBotHandler.php b/src/Monolog/Handler/TelegramBotHandler.php
index feaa002f..8fda7697 100644
--- a/src/Monolog/Handler/TelegramBotHandler.php
+++ b/src/Monolog/Handler/TelegramBotHandler.php
@@ -111,9 +111,9 @@ class TelegramBotHandler extends AbstractProcessingHandler
         string $channel,
         $level = Level::Debug,
         bool   $bubble = true,
-        string $parseMode = null,
-        bool   $disableWebPagePreview = null,
-        bool   $disableNotification = null,
+        ?string $parseMode = null,
+        ?bool   $disableWebPagePreview = null,
+        ?bool   $disableNotification = null,
         bool   $splitLongMessages = false,
         bool   $delayBetweenMessages = false,
         int    $topic = null
@@ -137,7 +137,7 @@ class TelegramBotHandler extends AbstractProcessingHandler
     /**
      * @return $this
      */
-    public function setParseMode(string $parseMode = null): self
+    public function setParseMode(string|null $parseMode = null): self
     {
         if ($parseMode !== null && !in_array($parseMode, self::AVAILABLE_PARSE_MODES, true)) {
             throw new \InvalidArgumentException('Unknown parseMode, use one of these: ' . implode(', ', self::AVAILABLE_PARSE_MODES) . '.');
@@ -151,7 +151,7 @@ class TelegramBotHandler extends AbstractProcessingHandler
     /**
      * @return $this
      */
-    public function disableWebPagePreview(bool $disableWebPagePreview = null): self
+    public function disableWebPagePreview(bool|null $disableWebPagePreview = null): self
     {
         $this->disableWebPagePreview = $disableWebPagePreview;
 
@@ -161,7 +161,7 @@ class TelegramBotHandler extends AbstractProcessingHandler
     /**
      * @return $this
      */
-    public function disableNotification(bool $disableNotification = null): self
+    public function disableNotification(bool|null $disableNotification = null): self
     {
         $this->disableNotification = $disableNotification;
 
diff --git a/src/Monolog/Logger.php b/src/Monolog/Logger.php
index b04194bf..f33c08f8 100644
--- a/src/Monolog/Logger.php
+++ b/src/Monolog/Logger.php
@@ -320,15 +320,15 @@ class Logger implements LoggerInterface, ResettableInterface
     /**
      * Adds a log record.
      *
-     * @param  int               $level    The logging level (a Monolog or RFC 5424 level)
-     * @param  string            $message  The log message
-     * @param  mixed[]           $context  The log context
-     * @param  DateTimeImmutable $datetime Optional log date to log into the past or future
-     * @return bool              Whether the record has been processed
+     * @param  int                    $level    The logging level (a Monolog or RFC 5424 level)
+     * @param  string                 $message  The log message
+     * @param  mixed[]                $context  The log context
+     * @param  DateTimeImmutable|null $datetime Optional log date to log into the past or future
+     * @return bool                   Whether the record has been processed
      *
      * @phpstan-param value-of<Level::VALUES>|Level $level
      */
-    public function addRecord(int|Level $level, string $message, array $context = [], DateTimeImmutable $datetime = null): bool
+    public function addRecord(int|Level $level, string $message, array $context = [], DateTimeImmutable|null $datetime = null): bool
     {
         if (is_int($level) && isset(self::RFC_5424_LEVELS[$level])) {
             $level = self::RFC_5424_LEVELS[$level];
diff --git a/tests/Monolog/SignalHandlerTest.php b/tests/Monolog/SignalHandlerTest.php
index addcb8c1..e4e9cffd 100644
--- a/tests/Monolog/SignalHandlerTest.php
+++ b/tests/Monolog/SignalHandlerTest.php
@@ -34,7 +34,7 @@ class SignalHandlerTest extends TestCase
                 $this->asyncSignalHandling = pcntl_async_signals();
             }
             if (function_exists('pcntl_sigprocmask')) {
-                pcntl_sigprocmask(SIG_BLOCK, [], $this->blockedSignals);
+                pcntl_sigprocmask(SIG_SETMASK, [], $this->blockedSignals);
             }
         }
     }
@@ -146,7 +146,7 @@ class SignalHandlerTest extends TestCase
             posix_kill(posix_getpid(), $signo);
             pcntl_signal_dispatch();
             // If $callPrevious is true, SIGINT should terminate by this line.
-            pcntl_sigprocmask(SIG_BLOCK, [], $oldset);
+            pcntl_sigprocmask(SIG_SETMASK, [], $oldset);
             file_put_contents($path, implode(' ', $oldset), FILE_APPEND);
             posix_kill(posix_getpid(), $signo);
             pcntl_signal_dispatch();