diff --git a/.travis.yml b/.travis.yml
index f0fe0a5..eea6edb 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -12,6 +12,7 @@ branches:
 matrix:
     fast_finish: true
     include:
+        - php: 7.4
         - php: 7.3
         - php: 7.2
         - php: 7.1
diff --git a/src/Command/Queue/Pull/MemoryUniquePullCommandQueue.php b/src/Command/Queue/Pull/MemoryUniquePullCommandQueue.php
index 78d36e8..5a69578 100644
--- a/src/Command/Queue/Pull/MemoryUniquePullCommandQueue.php
+++ b/src/Command/Queue/Pull/MemoryUniquePullCommandQueue.php
@@ -31,7 +31,7 @@ public function publish(Command $command)
         $index = array_search($command, $this->commands);
 
         // remove exists command and publish it again
-        if ($index !== false) {
+        if (false !== $index) {
             unset($this->commands[$index]);
         }
 
diff --git a/src/Command/Queue/Subscribe/ExecutingSubscribeCommandQueue.php b/src/Command/Queue/Subscribe/ExecutingSubscribeCommandQueue.php
index df4a815..0503949 100644
--- a/src/Command/Queue/Subscribe/ExecutingSubscribeCommandQueue.php
+++ b/src/Command/Queue/Subscribe/ExecutingSubscribeCommandQueue.php
@@ -57,7 +57,7 @@ public function unsubscribe(callable $handler)
     {
         $index = array_search($handler, $this->handlers);
 
-        if ($index === false) {
+        if (false === $index) {
             return false;
         }
 
diff --git a/src/Command/Queue/Subscribe/PredisSubscribeCommandQueue.php b/src/Command/Queue/Subscribe/PredisSubscribeCommandQueue.php
index 1f58cfb..c9c9288 100644
--- a/src/Command/Queue/Subscribe/PredisSubscribeCommandQueue.php
+++ b/src/Command/Queue/Subscribe/PredisSubscribeCommandQueue.php
@@ -109,7 +109,7 @@ public function unsubscribe(callable $handler)
     {
         $index = array_search($handler, $this->handlers);
 
-        if ($index === false) {
+        if (false === $index) {
             return false;
         }