diff --git a/php/src/Container/ContainerVolumes.php b/php/src/Container/ContainerVolumes.php
index 873be1f4..23618df4 100644
--- a/php/src/Container/ContainerVolumes.php
+++ b/php/src/Container/ContainerVolumes.php
@@ -6,7 +6,7 @@ class ContainerVolumes {
     /** @var ContainerVolume[] */
     private array $volumes = [];
 
-    public function AddVolume(ContainerVolume $volume) {
+    public function AddVolume(ContainerVolume $volume) : void {
         $this->volumes[] = $volume;
     }
 
diff --git a/php/src/Controller/DockerController.php b/php/src/Controller/DockerController.php
index 556f7bb8..7de6c1dd 100644
--- a/php/src/Controller/DockerController.php
+++ b/php/src/Controller/DockerController.php
@@ -26,7 +26,7 @@ class DockerController
         $this->configurationManager = $configurationManager;
     }
 
-    private function PerformRecursiveContainerStart(string $id) {
+    private function PerformRecursiveContainerStart(string $id) : void {
         $container = $this->containerDefinitionFetcher->GetContainerById($id);
 
         foreach($container->GetDependsOn() as $dependency) {
@@ -126,7 +126,7 @@ class DockerController
         return $response->withStatus(201)->withHeader('Location', '/');
     }
 
-    private function PerformRecursiveContainerStop(string $id)
+    private function PerformRecursiveContainerStop(string $id) : void
     {
         $container = $this->containerDefinitionFetcher->GetContainerById($id);
         foreach($container->GetDependsOn() as $dependency) {
@@ -146,7 +146,7 @@ class DockerController
         return $response->withStatus(201)->withHeader('Location', '/');
     }
 
-    public function StartDomaincheckContainer()
+    public function StartDomaincheckContainer() : void
     {
         # Don't start if domain is already set
         if ($this->configurationManager->GetDomain() != '') {
@@ -167,7 +167,7 @@ class DockerController
         $this->PerformRecursiveContainerStart($id);
     }
 
-    private function StopDomaincheckContainer()
+    private function StopDomaincheckContainer() : void
     {
         $id = 'nextcloud-aio-domaincheck';
         $this->PerformRecursiveContainerStop($id);
diff --git a/php/src/Data/ConfigurationManager.php b/php/src/Data/ConfigurationManager.php
index c43956fc..f98cab2b 100644
--- a/php/src/Data/ConfigurationManager.php
+++ b/php/src/Data/ConfigurationManager.php
@@ -46,7 +46,7 @@ class ConfigurationManager
         return $config['secrets'][$secretId];
     }
 
-    private function DoubleSafeBackupSecret(string $borgBackupPassword) {
+    private function DoubleSafeBackupSecret(string $borgBackupPassword) : void {
         file_put_contents(DataConst::GetBackupSecretFile(), $borgBackupPassword);
     }
 
@@ -101,10 +101,6 @@ class ConfigurationManager
                 $backupTimes[] = $backupTimesTemp[1];     
             }
         }
-        
-        if (!is_array($backupTimes)) {
-            return [];
-        }
 
         return $backupTimes;
     }
diff --git a/php/src/Docker/DockerActionManager.php b/php/src/Docker/DockerActionManager.php
index 88bb3093..dd695f7b 100644
--- a/php/src/Docker/DockerActionManager.php
+++ b/php/src/Docker/DockerActionManager.php
@@ -109,7 +109,7 @@ class DockerActionManager
         }
     }
 
-    public function DeleteContainer(Container $container) {
+    public function DeleteContainer(Container $container) : void {
         $url = $this->BuildApiUrl(sprintf('containers/%s?v=true', urlencode($container->GetIdentifier())));
         try {
             $this->guzzleClient->delete($url);
@@ -142,12 +142,12 @@ class DockerActionManager
         return $response;
     }
 
-    public function StartContainer(Container $container) {
+    public function StartContainer(Container $container) : void {
         $url = $this->BuildApiUrl(sprintf('containers/%s/start', urlencode($container->GetIdentifier())));
         $this->guzzleClient->post($url);
     }
 
-    public function CreateVolumes(Container $container)
+    public function CreateVolumes(Container $container): void
     {
         $url = $this->BuildApiUrl('volumes/create');
         foreach($container->GetVolumes()->GetVolumes() as $volume) {
@@ -170,7 +170,7 @@ class DockerActionManager
         }
     }
 
-    public function CreateContainer(Container $container) {
+    public function CreateContainer(Container $container) : void {
         $volumes = [];
         foreach($container->GetVolumes()->GetVolumes() as $volume) {
             $volumeEntry = $volume->name . ':' . $volume->mountPoint;
@@ -259,7 +259,7 @@ class DockerActionManager
         );
     }
 
-    public function PullContainer(Container $container)
+    public function PullContainer(Container $container) : void
     {
         $url = $this->BuildApiUrl(sprintf('images/create?fromImage=%s', urlencode($this->BuildImageName($container))));
         try {
@@ -283,10 +283,9 @@ class DockerActionManager
         return $updateAvailable;
     }
 
-    public function isAnyUpdateAvailable() {
+    public function isAnyUpdateAvailable() : bool {
         $id = 'nextcloud-aio-apache';
 
-
         if ($this->isContainerUpdateAvailable($id) !== "") {
             return true;
         } else {
@@ -354,7 +353,7 @@ class DockerActionManager
         }
     }
 
-    public function sendNotification(Container $container, string $subject, string $message)
+    public function sendNotification(Container $container, string $subject, string $message) : void
     {
         if ($this->GetContainerStartingState($container) instanceof RunningState) {
 
@@ -400,7 +399,7 @@ class DockerActionManager
         }
     }
 
-    public function DisconnectContainerFromNetwork(Container $container)
+    public function DisconnectContainerFromNetwork(Container $container) : void
     {
 
         $url = $this->BuildApiUrl(
@@ -421,7 +420,7 @@ class DockerActionManager
         }
     }
 
-    private function ConnectContainerIdToNetwork(string $id)
+    private function ConnectContainerIdToNetwork(string $id) : void
     {
         $url = $this->BuildApiUrl('networks/create');
         try {
@@ -464,17 +463,17 @@ class DockerActionManager
         }
     }
 
-    public function ConnectMasterContainerToNetwork()
+    public function ConnectMasterContainerToNetwork() : void
     {
         $this->ConnectContainerIdToNetwork('nextcloud-aio-mastercontainer');
     }
 
-    public function ConnectContainerToNetwork(Container $container)
+    public function ConnectContainerToNetwork(Container $container) : void
     {
       $this->ConnectContainerIdToNetwork($container->GetIdentifier());
     }
 
-    public function StopContainer(Container $container) {
+    public function StopContainer(Container $container) : void {
         $url = $this->BuildApiUrl(sprintf('containers/%s/stop?t=%s', urlencode($container->GetIdentifier()), $container->GetMaxShutdownTime()));
         try {
             $this->guzzleClient->post($url);