diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 96cd3be8..c1d3f18b 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -17,7 +17,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2' ]
+        php: [ '7.2', '7.3', '7.4', '8.0', '8.1', '8.2', '8.3' ]
         os: [ 'ubuntu-latest' ]
 
     steps:
@@ -32,12 +32,12 @@ jobs:
 
       - name: Setup dependencies
         run: |
-          composer require -n --no-progress overtrue/phplint
-          git clone --depth 1 https://github.com/Icinga/icingaweb2.git vendor/icingaweb2
-          git clone --depth 1 https://github.com/Icinga/icingadb-web.git vendor/icingadb
-          git clone --depth 1 https://github.com/Icinga/icingaweb2-module-pdfexport.git vendor/pdfexport
-          git clone --depth 1 -b snapshot/nightly https://github.com/Icinga/icinga-php-library.git vendor/icinga-php-library
-          git clone --depth 1 -b snapshot/nightly https://github.com/Icinga/icinga-php-thirdparty.git vendor/icinga-php-thirdparty
+          composer require -n --no-progress overtrue/phplint phpstan/phpstan
+          sudo git clone --depth 1 https://github.com/Icinga/icingaweb2.git /icingaweb2
+          sudo git clone --depth 1 https://github.com/Icinga/icingadb-web.git /usr/share/icingaweb2-modules/icingadb
+          sudo git clone --depth 1 https://github.com/Icinga/icingaweb2-module-pdfexport.git /usr/share/icingaweb2-modules/pdfexport
+          sudo git clone --depth 1 -b snapshot/nightly https://github.com/Icinga/icinga-php-library.git /usr/share/icinga-php/ipl
+          sudo git clone --depth 1 -b snapshot/nightly https://github.com/Icinga/icinga-php-thirdparty.git /usr/share/icinga-php/vendor
 
       - name: PHP Lint
         if: ${{ ! cancelled() }}
@@ -49,4 +49,4 @@ jobs:
 
       - name: PHPStan
         if: ${{ ! cancelled() }}
-        uses: php-actions/phpstan@v3
+        run: ./vendor/bin/phpstan analyse
diff --git a/application/clicommands/DownloadCommand.php b/application/clicommands/DownloadCommand.php
index 94a8c2aa..9b7c99d9 100644
--- a/application/clicommands/DownloadCommand.php
+++ b/application/clicommands/DownloadCommand.php
@@ -60,7 +60,9 @@ public function defaultAction()
 
         $report = Report::fromModel($report);
 
-        $format = strtolower($this->params->get('format', 'pdf'));
+        /** @var string $format */
+        $format = $this->params->get('format', 'pdf');
+        $format = strtolower($format);
         switch ($format) {
             case 'pdf':
                 $content = Pdfexport::first()->htmlToPdf($report->toPdf());
@@ -75,6 +77,7 @@ public function defaultAction()
                 throw new InvalidArgumentException(sprintf('Format %s is not supported', $format));
         }
 
+        /** @var string $output */
         $output = $this->params->get('output');
         if ($output === null) {
             $name = sprintf(
diff --git a/application/clicommands/ListCommand.php b/application/clicommands/ListCommand.php
index c26a3d3a..2486ae0f 100644
--- a/application/clicommands/ListCommand.php
+++ b/application/clicommands/ListCommand.php
@@ -49,7 +49,9 @@ class ListCommand extends Command
      */
     public function indexAction()
     {
-        $sort = strtolower($this->params->get('sort', 'id'));
+        /** @var string $sort */
+        $sort = $this->params->get('sort', 'id');
+        $sort = strtolower($sort);
 
         if ($sort !== 'id' && $sort !== 'name' && $sort !== 'author') {
             throw new InvalidArgumentException(sprintf('Sorting by %s is not supported', $sort));
diff --git a/library/Reporting/Actions/SendMail.php b/library/Reporting/Actions/SendMail.php
index 122af0b8..a0dc42f6 100644
--- a/library/Reporting/Actions/SendMail.php
+++ b/library/Reporting/Actions/SendMail.php
@@ -57,9 +57,10 @@ public function execute(Report $report, array $config)
                 throw new \InvalidArgumentException();
         }
 
-        $recipients = array_filter(preg_split('/[\s,]+/', $config['recipients']));
+        /** @var array<int, string> $recipients */
+        $recipients = preg_split('/[\s,]+/', $config['recipients']);
 
-        $mail->send(null, $recipients);
+        $mail->send(null, array_filter($recipients));
     }
 
     public function initConfigForm(Form $form, Report $report)
diff --git a/library/Reporting/Reports/SystemReport.php b/library/Reporting/Reports/SystemReport.php
index 32f63b86..5c9a5445 100644
--- a/library/Reporting/Reports/SystemReport.php
+++ b/library/Reporting/Reports/SystemReport.php
@@ -20,6 +20,7 @@ public function getHtml(Timerange $timerange, array $config = null)
     {
         ob_start();
         phpinfo();
+        /** @var string $html */
         $html = ob_get_clean();
 
         if (! Icinga::app()->isCli()) {
diff --git a/library/Reporting/Str.php b/library/Reporting/Str.php
index 7c6a7c05..77eb65e8 100644
--- a/library/Reporting/Str.php
+++ b/library/Reporting/Str.php
@@ -8,6 +8,7 @@ class Str
 {
     public static function putcsv(array $data, $delimiter = ',', $enclosure = '"', $escape = '\\')
     {
+        /** @var resource $fp */
         $fp = fopen('php://temp', 'r+b');
 
         foreach ($data as $row) {
@@ -16,6 +17,7 @@ public static function putcsv(array $data, $delimiter = ',', $enclosure = '"', $
 
         rewind($fp);
 
+        /** @var string $csv */
         $csv = stream_get_contents($fp);
 
         fclose($fp);
diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index 3e721e84..4799ad3f 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -5,36 +5,11 @@ parameters:
 			count: 1
 			path: application/clicommands/DownloadCommand.php
 
-		-
-			message: "#^Parameter \\#1 \\$filename of function file_put_contents expects string, mixed given\\.$#"
-			count: 1
-			path: application/clicommands/DownloadCommand.php
-
-		-
-			message: "#^Parameter \\#1 \\$filename of function is_dir expects string, mixed given\\.$#"
-			count: 1
-			path: application/clicommands/DownloadCommand.php
-
-		-
-			message: "#^Parameter \\#1 \\$string of function strtolower expects string, mixed given\\.$#"
-			count: 1
-			path: application/clicommands/DownloadCommand.php
-
 		-
 			message: "#^Parameter \\#2 \\$value of static method ipl\\\\Stdlib\\\\Filter\\:\\:equal\\(\\) expects array\\|bool\\|float\\|int\\|string, mixed given\\.$#"
 			count: 1
 			path: application/clicommands/DownloadCommand.php
 
-		-
-			message: "#^Parameter \\#2 \\.\\.\\.\\$values of function sprintf expects bool\\|float\\|int\\|string\\|null, mixed given\\.$#"
-			count: 1
-			path: application/clicommands/DownloadCommand.php
-
-		-
-			message: "#^Part \\$output \\(mixed\\) of encapsed string cannot be cast to string\\.$#"
-			count: 1
-			path: application/clicommands/DownloadCommand.php
-
 		-
 			message: "#^Call to an undefined method object\\:\\:getName\\(\\)\\.$#"
 			count: 1
@@ -65,11 +40,6 @@ parameters:
 			count: 1
 			path: application/clicommands/ListCommand.php
 
-		-
-			message: "#^Parameter \\#1 \\$string of function strtolower expects string, mixed given\\.$#"
-			count: 1
-			path: application/clicommands/ListCommand.php
-
 		-
 			message: "#^Parameter \\#2 \\$direction of method ipl\\\\Orm\\\\Query\\:\\:orderBy\\(\\) expects int\\|string\\|null, mixed given\\.$#"
 			count: 1
@@ -280,11 +250,6 @@ parameters:
 			count: 1
 			path: library/Reporting/Actions/SendMail.php
 
-		-
-			message: "#^Parameter \\#1 \\$array of function array_filter expects array, array\\<int, string\\>\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Actions/SendMail.php
-
 		-
 			message: "#^Parameter \\#1 \\$from of method Icinga\\\\Module\\\\Reporting\\\\Mail\\:\\:setFrom\\(\\) expects string, mixed given\\.$#"
 			count: 1
@@ -695,16 +660,6 @@ parameters:
 			count: 1
 			path: library/Reporting/Reports/SystemReport.php
 
-		-
-			message: "#^Parameter \\#1 \\$source of method DOMDocument\\:\\:loadHTML\\(\\) expects string, string\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Reports/SystemReport.php
-
-		-
-			message: "#^Parameter \\#1 \\$string of function nl2br expects string, string\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Reports/SystemReport.php
-
 		-
 			message: "#^Method Icinga\\\\Module\\\\Reporting\\\\RetryConnection\\:\\:prepexec\\(\\) has parameter \\$values with no value type specified in iterable type array\\.$#"
 			count: 1
@@ -780,31 +735,6 @@ parameters:
 			count: 1
 			path: library/Reporting/Str.php
 
-		-
-			message: "#^Parameter \\#1 \\$stream of function fclose expects resource, resource\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Str.php
-
-		-
-			message: "#^Parameter \\#1 \\$stream of function fputcsv expects resource, resource\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Str.php
-
-		-
-			message: "#^Parameter \\#1 \\$stream of function rewind expects resource, resource\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Str.php
-
-		-
-			message: "#^Parameter \\#1 \\$stream of function stream_get_contents expects resource, resource\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Str.php
-
-		-
-			message: "#^Parameter \\#1 \\$string of function rtrim expects string, string\\|false given\\.$#"
-			count: 1
-			path: library/Reporting/Str.php
-
 		-
 			message: "#^Method Icinga\\\\Module\\\\Reporting\\\\Timeframe\\:\\:getTimerange\\(\\) has no return type specified\\.$#"
 			count: 1
diff --git a/phpstan.neon b/phpstan.neon
index 264c33dc..b540b892 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -13,7 +13,11 @@ parameters:
         - library
 
     scanDirectories:
-        - vendor
+        - /icingaweb2
+        - /usr/share/icinga-php/ipl
+        - /usr/share/icinga-php/vendor
+        - /usr/share/icingaweb2-modules/icingadb
+        - /usr/share/icingaweb2-modules/pdfexport
 
     ignoreErrors:
         -