diff --git a/composer.json b/composer.json
index fbb7de7..72c0cdb 100644
--- a/composer.json
+++ b/composer.json
@@ -2,12 +2,12 @@
     "name": "zwirek/react-timer-handler",
     "type": "library",
     "description": "Simple handler for ReactPHP timers",
-    "keywords": ["ReactPHP", "Timer", "react", "handler"],
+    "keywords": ["ReactPHP", "Timer", "react", "handler", "php", "async"],
     "license": "MIT",
     "authors": [
         {
             "name": "Zbigniew Żwirek",
-            "email": "git.srv@zwirek.net"
+            "email": "github.srv@zwirek.net"
         }
     ],
     "autoload": {
@@ -21,10 +21,10 @@
         }
     },
     "require": {
-        "php": "^7.1",
+        "php": ">=8.1",
         "react/event-loop": "^1.1"
     },
     "require-dev": {
-        "phpunit/phpunit": "^8.2 || ^7.0 || ^6.4 || ^5.7"
+        "phpunit/phpunit": "^8.2"
     }
 }
diff --git a/src/TimerHandler.php b/src/TimerHandler.php
index 145c332..48cc608 100644
--- a/src/TimerHandler.php
+++ b/src/TimerHandler.php
@@ -11,17 +11,17 @@ final class TimerHandler implements TimerHandlerInterface
     /**
      * @var LoopInterface
      */
-    private $loop;
+    private LoopInterface $loop;
 
     /**
      * @var TimerInterface[]
      */
-    private $timers = [];
+    private array $timers = [];
 
     /**
      * @var int[]
      */
-    private $limitedPeriodicTimerCounters = [];
+    private array $limitedPeriodicTimerCounters = [];
 
     public function __construct(LoopInterface $loop)
     {
@@ -43,7 +43,7 @@ public function addTimer(string $name, $interval, callable $callback): bool
             $this->timers[$name] = null;
             unset($this->timers[$name]);
 
-            call_user_func($callback, $timer);
+            $callback($timer);
         });
 
         return true;
@@ -106,9 +106,9 @@ public function addLimitedPeriodicTimer(string $name, $interval, callable $callb
         $this->limitedPeriodicTimerCounters[$name] = 0;
 
         $this->timers[$name] = $this->loop->addPeriodicTimer($interval, function (TimerInterface $timer) use ($callback, $name, $callLimit) {
-            call_user_func($callback, $timer);
+            $callback($timer);
 
-            if (++$this->limitedPeriodicTimerCounters >= $callLimit) {
+            if (++$this->limitedPeriodicTimerCounters[$name] >= $callLimit) {
                 $this->loop->cancelTimer($timer);
                 $this->timers[$name] = null;
                 unset($this->timers[$name]);
diff --git a/tests/TimerHandlerTest.php b/tests/TimerHandlerTest.php
index 642a325..9631731 100644
--- a/tests/TimerHandlerTest.php
+++ b/tests/TimerHandlerTest.php
@@ -76,10 +76,10 @@ public function shouldPassBindParameters()
     {
         $timerHandler = new TimerHandler($this->loop);
 
-        $parameter = 'binded parameter';
+        $parameter = 'bound parameter';
 
         $timerHandler->addTimer('test', 0.005, function() use ($parameter) {
-            self::assertEquals('bind parameter', $parameter);
+            self::assertEquals('bound parameter', $parameter);
 
             $this->assertLoop();
         });
@@ -157,7 +157,7 @@ public function shouldCallTimerAFewTimes()
         $timerHandler->addLimitedPeriodicTimer('limited', 0.005, function() use (&$counter) {
             $counter++;
 
-            if ($counter = 5) {
+            if ($counter === 5) {
                 $this->assertLoop();
             }
         }, 5);