diff --git a/CHANGELOG.md b/CHANGELOG.md
index 167b9b8..c14ca1d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # Changelog
 
+## [Unreleased]
+
+### Fixed
+
+- PHP `8.4` deprecations
+
 ## 5.2.0 - 2024-07-14
 
 ### Changed
diff --git a/src/Factory.php b/src/Factory.php
index e3973b2..932ea38 100644
--- a/src/Factory.php
+++ b/src/Factory.php
@@ -5,7 +5,7 @@
 
 final class Factory
 {
-    public static function build(Config $config = null): OperatingSystem
+    public static function build(?Config $config = null): OperatingSystem
     {
         switch (\PHP_OS) {
             case 'Darwin':
diff --git a/src/OperatingSystem/Unix.php b/src/OperatingSystem/Unix.php
index fcc5768..e646d0b 100644
--- a/src/OperatingSystem/Unix.php
+++ b/src/OperatingSystem/Unix.php
@@ -38,7 +38,7 @@ private function __construct(Config $config)
         $this->config = $config;
     }
 
-    public static function of(Config $config = null): self
+    public static function of(?Config $config = null): self
     {
         return new self($config ?? Config::of());
     }
diff --git a/src/Sockets.php b/src/Sockets.php
index 3d9ffa2..44b045a 100644
--- a/src/Sockets.php
+++ b/src/Sockets.php
@@ -32,5 +32,5 @@ public function takeOver(Unix $address): Maybe;
      * @return Maybe<Client>
      */
     public function connectTo(Unix $address): Maybe;
-    public function watch(ElapsedPeriod $timeout = null): Watch;
+    public function watch(?ElapsedPeriod $timeout = null): Watch;
 }
diff --git a/src/Sockets/Logger.php b/src/Sockets/Logger.php
index 4ce3a25..29b0fdb 100644
--- a/src/Sockets/Logger.php
+++ b/src/Sockets/Logger.php
@@ -56,7 +56,7 @@ public function connectTo(Address $address): Maybe
         return $this->sockets->connectTo($address);
     }
 
-    public function watch(ElapsedPeriod $timeout = null): Watch
+    public function watch(?ElapsedPeriod $timeout = null): Watch
     {
         return Watch\Logger::psr(
             $this->sockets->watch($timeout),
diff --git a/src/Sockets/Unix.php b/src/Sockets/Unix.php
index 3b29b63..0f701a8 100644
--- a/src/Sockets/Unix.php
+++ b/src/Sockets/Unix.php
@@ -54,7 +54,7 @@ public function connectTo(Address $address): Maybe
         );
     }
 
-    public function watch(ElapsedPeriod $timeout = null): Watch
+    public function watch(?ElapsedPeriod $timeout = null): Watch
     {
         if (\is_null($timeout)) {
             return $this