diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 1074ce56..fdb9b3bf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -18,6 +18,3 @@ jobs:
     uses: matomo-org/plugin-ci-workflows/.github/workflows/plugin-ci.yml@main
     with:
       plugin-name: DeviceDetectorCache
-      # PHPStan has never run here and there is no phpstan.neon to run it with;
-      # adding one is a decision of its own.
-      skip-phpstan: true
diff --git a/CachedEntry.php b/CachedEntry.php
index 5291e71a..e3ae19d2 100644
--- a/CachedEntry.php
+++ b/CachedEntry.php
@@ -23,7 +23,7 @@ class CachedEntry extends DeviceDetector
     private static $CACHE_DIR = '';
     private static $customCache = null;
 
-    public function __construct(string $userAgent, $clientHints, array $values)
+    public function __construct(string $userAgent, array $clientHints, array $values)
     {
         $clientHints = $clientHints ? ClientHints::factory($clientHints) : null;
         parent::__construct($userAgent, $clientHints);
diff --git a/Commands/WarmDeviceDetectorCache.php b/Commands/WarmDeviceDetectorCache.php
index 336d9c49..681589f7 100644
--- a/Commands/WarmDeviceDetectorCache.php
+++ b/Commands/WarmDeviceDetectorCache.php
@@ -164,7 +164,7 @@ protected function doExecute(): int
             if ($i <= 10) {
                 $this->log('Found user agent ' . $agent . ' count: ' . $val);
             }
-            CachedEntry::writeToCache($agent, []);
+            CachedEntry::writeToCache($agent);
             // sleep 2ms to let CPU do something else
             // this will make things about 10m slower for 200K entries but at least sudden CPU increase for instance
             // can be prevented when there are only few CPUs available
diff --git a/Configuration.php b/Configuration.php
index c95cb1a5..be117dec 100644
--- a/Configuration.php
+++ b/Configuration.php
@@ -78,7 +78,7 @@ public function getAccessLogRegex()
     }
 
     /**
-     * @return string
+     * @return int
      */
     public function getRegexMatchEntry()
     {
@@ -86,7 +86,7 @@ public function getRegexMatchEntry()
     }
 
     /**
-     * @return string
+     * @return int
      */
     public function getNumEntriesToCache()
     {
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 00000000..6058b356
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,19 @@
+parameters:
+    level: 5
+    phpVersion: 80100
+    tmpDir: /tmp/phpstan/DeviceDetectorCache/main
+    paths:
+        - .
+    excludePaths:
+        - tests/*
+        # The shared workflow leaves this helper checkout in the workspace, and `paths: .`
+        # would otherwise analyse it as if it were plugin code.
+        - github-action-tests/*
+    bootstrapFiles:
+        - ../../bootstrap-phpstan.php
+    universalObjectCratesClasses:
+        - Piwik\Config
+        - Piwik\View
+        - Piwik\ViewDataTable\Config
+    scanDirectories:
+        - ../../
diff --git a/tests/Integration/CachedEntryTest.php b/tests/Integration/CachedEntryTest.php
index c2e29043..32393a2d 100644
--- a/tests/Integration/CachedEntryTest.php
+++ b/tests/Integration/CachedEntryTest.php
@@ -165,11 +165,11 @@ public function testGetNumCacheFiles_noneCached()
 
     public function testGetNumCacheFiles()
     {
-        CachedEntry::writeToCache('foo', []);
+        CachedEntry::writeToCache('foo');
         $this->assertEquals(1, CachedEntry::getNumEntriesInCacheDir());
-        CachedEntry::writeToCache('bar', []);
+        CachedEntry::writeToCache('bar');
         $this->assertEquals(2, CachedEntry::getNumEntriesInCacheDir());
-        CachedEntry::writeToCache('baz', []);
+        CachedEntry::writeToCache('baz');
         $this->assertEquals(3, CachedEntry::getNumEntriesInCacheDir());
     }
 
@@ -180,7 +180,7 @@ public function testGetCached_noEntry()
 
     public function test_writeToCache_GetCached()
     {
-        CachedEntry::writeToCache('foo', []);
+        CachedEntry::writeToCache('foo');
         $cacheEntry = CachedEntry::getCached('foo', []);
         $this->assertEquals(
             [
@@ -212,7 +212,7 @@ public function test_getCacheDir()
 
     public function test_deleteLeastAccessedFiles_nothingToDelete()
     {
-        $filePath = CachedEntry::writeToCache('file', []);
+        $filePath = CachedEntry::writeToCache('file');
         $this->assertFileExists($filePath);
 
         CachedEntry::deleteLeastAccessedFiles(-1);
@@ -223,13 +223,13 @@ public function test_deleteLeastAccessedFiles_nothingToDelete()
 
     public function test_deleteLeastAccessedFiles_deletesOnlyOldest()
     {
-        $filePath1 = CachedEntry::writeToCache('file', []);
+        $filePath1 = CachedEntry::writeToCache('file');
         sleep(1); // otherwise without sleep the sorting won't work properly
-        $filePath2 = CachedEntry::writeToCache('bar', []);
+        $filePath2 = CachedEntry::writeToCache('bar');
         sleep(1);
-        $filePath3 = CachedEntry::writeToCache('baz', []);
+        $filePath3 = CachedEntry::writeToCache('baz');
         sleep(1);
-        $filePath4 = CachedEntry::writeToCache('foo', []);
+        $filePath4 = CachedEntry::writeToCache('foo');
         sleep(1);
 
         CachedEntry::deleteLeastAccessedFiles(2);
@@ -242,13 +242,13 @@ public function test_deleteLeastAccessedFiles_deletesOnlyOldest()
 
     public function test_deleteLeastAccessedFiles_deletesOnlyOldest2()
     {
-        $filePath1 = CachedEntry::writeToCache('file', []);
+        $filePath1 = CachedEntry::writeToCache('file');
         sleep(1);
-        $filePath2 = CachedEntry::writeToCache('bar', []);
+        $filePath2 = CachedEntry::writeToCache('bar');
         sleep(1);
-        $filePath3 = CachedEntry::writeToCache('baz', []);
+        $filePath3 = CachedEntry::writeToCache('baz');
         sleep(1);
-        $filePath4 = CachedEntry::writeToCache('foo', []);
+        $filePath4 = CachedEntry::writeToCache('foo');
         sleep(1);
 
         touch($filePath1);