diff --git a/src/Monolog/Handler/FilterHandler.php b/src/Monolog/Handler/FilterHandler.php
index 718f17ef1..5e43e1dc2 100644
--- a/src/Monolog/Handler/FilterHandler.php
+++ b/src/Monolog/Handler/FilterHandler.php
@@ -161,7 +161,7 @@ public function handleBatch(array $records): void
      *
      * @phpstan-param Record $record
      */
-    public function getHandler(array $record = null)
+    public function getHandler(?array $record = null)
     {
         if (!$this->handler instanceof HandlerInterface) {
             $this->handler = ($this->handler)($record, $this);
diff --git a/src/Monolog/Handler/FingersCrossedHandler.php b/src/Monolog/Handler/FingersCrossedHandler.php
index 0627b4451..dfcb3af28 100644
--- a/src/Monolog/Handler/FingersCrossedHandler.php
+++ b/src/Monolog/Handler/FingersCrossedHandler.php
@@ -210,7 +210,7 @@ private function flushBuffer(): void
      *
      * @phpstan-param Record $record
      */
-    public function getHandler(array $record = null)
+    public function getHandler(?array $record = null)
     {
         if (!$this->handler instanceof HandlerInterface) {
             $this->handler = ($this->handler)($record, $this);
diff --git a/src/Monolog/Handler/SamplingHandler.php b/src/Monolog/Handler/SamplingHandler.php
index c128a32d1..25cce07f9 100644
--- a/src/Monolog/Handler/SamplingHandler.php
+++ b/src/Monolog/Handler/SamplingHandler.php
@@ -90,7 +90,7 @@ public function handle(array $record): bool
      *
      * @return HandlerInterface
      */
-    public function getHandler(array $record = null)
+    public function getHandler(?array $record = null)
     {
         if (!$this->handler instanceof HandlerInterface) {
             $this->handler = ($this->handler)($record, $this);
diff --git a/src/Monolog/Handler/Slack/SlackRecord.php b/src/Monolog/Handler/Slack/SlackRecord.php
index 71a410946..9ae100371 100644
--- a/src/Monolog/Handler/Slack/SlackRecord.php
+++ b/src/Monolog/Handler/Slack/SlackRecord.php
@@ -100,7 +100,7 @@ public function __construct(
         bool $useShortAttachment = false,
         bool $includeContextAndExtra = false,
         array $excludeFields = array(),
-        FormatterInterface $formatter = null
+        ?FormatterInterface $formatter = null
     ) {
         $this
             ->setChannel($channel)
diff --git a/src/Monolog/Handler/TelegramBotHandler.php b/src/Monolog/Handler/TelegramBotHandler.php
index 8912eba51..a6223b795 100644
--- a/src/Monolog/Handler/TelegramBotHandler.php
+++ b/src/Monolog/Handler/TelegramBotHandler.php
@@ -108,9 +108,9 @@ public function __construct(
         string $channel,
                $level = Logger::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
     )
@@ -130,7 +130,7 @@ public function __construct(
         $this->delayBetweenMessages($delayBetweenMessages);
     }
 
-    public function setParseMode(string $parseMode = null): self
+    public function setParseMode(?string $parseMode = null): self
     {
         if ($parseMode !== null && !in_array($parseMode, self::AVAILABLE_PARSE_MODES)) {
             throw new \InvalidArgumentException('Unknown parseMode, use one of these: ' . implode(', ', self::AVAILABLE_PARSE_MODES) . '.');
@@ -141,14 +141,14 @@ public function setParseMode(string $parseMode = null): self
         return $this;
     }
 
-    public function disableWebPagePreview(bool $disableWebPagePreview = null): self
+    public function disableWebPagePreview(?bool $disableWebPagePreview = null): self
     {
         $this->disableWebPagePreview = $disableWebPagePreview;
 
         return $this;
     }
 
-    public function disableNotification(bool $disableNotification = null): self
+    public function disableNotification(?bool $disableNotification = null): self
     {
         $this->disableNotification = $disableNotification;
 
diff --git a/src/Monolog/Logger.php b/src/Monolog/Logger.php
index 84a2f5510..3c588a707 100644
--- a/src/Monolog/Logger.php
+++ b/src/Monolog/Logger.php
@@ -337,7 +337,7 @@ public function useLoggingLoopDetection(bool $detectCycles): self
      *
      * @phpstan-param Level $level
      */
-    public function addRecord(int $level, string $message, array $context = [], DateTimeImmutable $datetime = null): bool
+    public function addRecord(int $level, string $message, array $context = [], ?DateTimeImmutable $datetime = null): bool
     {
         if (isset(self::RFC_5424_LEVELS[$level])) {
             $level = self::RFC_5424_LEVELS[$level];
diff --git a/src/Monolog/Processor/WebProcessor.php b/src/Monolog/Processor/WebProcessor.php
index 51850e17f..887f4d396 100644
--- a/src/Monolog/Processor/WebProcessor.php
+++ b/src/Monolog/Processor/WebProcessor.php
@@ -43,7 +43,7 @@ class WebProcessor implements ProcessorInterface
      * @param array<string, mixed>|\ArrayAccess<string, mixed>|null $serverData  Array or object w/ ArrayAccess that provides access to the $_SERVER data
      * @param array<string, string>|array<string>|null              $extraFields Field names and the related key inside $serverData to be added (or just a list of field names to use the default configured $serverData mapping). If not provided it defaults to: [url, ip, http_method, server, referrer] + unique_id if present in server data
      */
-    public function __construct($serverData = null, array $extraFields = null)
+    public function __construct($serverData = null, ?array $extraFields = null)
     {
         if (null === $serverData) {
             $this->serverData = &$_SERVER;