diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index b610b41..33eb815 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -115,7 +115,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php-versions }}
-          extensions: ctype, date, dom, fileinfo, filter, hash, intl, mbstring, openssl, pcre, posix, spl, xml
+          extensions: ctype, date, dom, fileinfo, filter, hash, intl, mbstring, openssl, pcre, posix, spl, xml, zip
           tools: composer
           ini-values: error_reporting=E_ALL
           coverage: none
@@ -161,9 +161,8 @@ jobs:
         with:
           # Should be the higest supported version, so we can use the newest tools
           php-version: '8.4'
-          tools: composer, composer-require-checker, composer-unused, phpcs, psalm
-          # optional performance gain for psalm: opcache
-          extensions: ctype, date, dom, fileinfo, filter, hash, intl, mbstring, opcache, openssl, pcre, posix, spl, xml
+          tools: composer, composer-require-checker, composer-unused, phpcs, phpstan
+          extensions: ctype, date, dom, fileinfo, filter, hash, intl, mbstring, openssl, pcre, posix, spl, xml
 
       - name: Setup problem matchers for PHP
         run: echo "::add-matcher::${{ runner.tool_cache }}/php.json"
@@ -195,27 +194,13 @@ jobs:
       - name: PHP Code Sniffer
         run: phpcs
 
-      - name: Psalm
-        continue-on-error: true
-        run: |
-          psalm -c psalm.xml \
-          --show-info=true \
-          --shepherd \
-          --php-version=${{ steps.setup-php.outputs.php-version }}
-
-      - name: Psalm (testsuite)
+      - name: PHPStan
         run: |
-          psalm -c psalm-dev.xml \
-          --show-info=true \
-          --shepherd \
-          --php-version=${{ steps.setup-php.outputs.php-version }}
+          vendor/bin/phpstan analyze -c phpstan.neon
 
-      - name: Psalter
+      - name: PHPStan (testsuite)
         run: |
-          psalm --alter \
-          --issues=UnnecessaryVarAnnotation \
-          --dry-run \
-          --php-version=${{ steps.setup-php.outputs.php-version }}
+          vendor/bin/phpstan analyze -c phpstan-dev.neon
 
   security:
     name: Security checks
diff --git a/phpstan-dev.neon b/phpstan-dev.neon
new file mode 100644
index 0000000..4d29b8b
--- /dev/null
+++ b/phpstan-dev.neon
@@ -0,0 +1,4 @@
+parameters:
+  level: 9
+  paths:
+    - tests
diff --git a/phpstan.neon b/phpstan.neon
new file mode 100644
index 0000000..db37782
--- /dev/null
+++ b/phpstan.neon
@@ -0,0 +1,4 @@
+parameters:
+  level: 6
+  paths:
+    - src
diff --git a/psalm-dev.xml b/psalm-dev.xml
deleted file mode 100644
index 95c5632..0000000
--- a/psalm-dev.xml
+++ /dev/null
@@ -1,18 +0,0 @@
-<?xml version="1.0"?>
-<psalm
-    name="SimpleSAMLphp testsuite"
-    useDocblockTypes="true"
-    errorLevel="4"
-    reportMixedIssues="false"
-    hideExternalErrors="true"
-    allowStringToStandInForClass="true"
->
-    <projectFiles>
-        <directory name="tests" />
-
-        <!-- Ignore certain directories -->
-        <ignoreFiles>
-            <directory name="vendor" />
-        </ignoreFiles>
-    </projectFiles>
-</psalm>
diff --git a/psalm.xml b/psalm.xml
deleted file mode 100644
index 4ea5604..0000000
--- a/psalm.xml
+++ /dev/null
@@ -1,30 +0,0 @@
-<?xml version="1.0"?>
-<psalm
-    name="SimpleSAMLphp Module entitycategories"
-    useDocblockTypes="true"
-    errorLevel="2"
-    reportMixedIssues="false"
->
-    <projectFiles>
-        <directory name="src" />
-    </projectFiles>
-
-    <issueHandlers>
-        <LessSpecificReturnType errorLevel="info" />
-
-        <!-- level 3 issues - slightly lazy code writing, but probably low false-negatives -->
-        <DeprecatedMethod errorLevel="info" />
-
-        <MissingClosureReturnType errorLevel="info" />
-        <MissingReturnType errorLevel="info" />
-        <MissingPropertyType errorLevel="info" />
-        <InvalidDocblock errorLevel="info" />
-
-        <PropertyNotSetInConstructor errorLevel="info" />
-        <MissingConstructor errorLevel="info" />
-        <MissingClosureParamType errorLevel="info" />
-        <MissingParamType errorLevel="info" />
-        <UnusedClass errorLevel="info" />
-        <PossiblyUnusedMethod errorLevel="info" />
-    </issueHandlers>
-</psalm>
diff --git a/src/Auth/Process/EntityCategory.php b/src/Auth/Process/EntityCategory.php
index 82d8759..4e616f3 100644
--- a/src/Auth/Process/EntityCategory.php
+++ b/src/Auth/Process/EntityCategory.php
@@ -27,7 +27,7 @@ class EntityCategory extends Auth\ProcessingFilter
      * A list of categories available. An associative array where the identifier of the category is the key, and the
      * associated value is an array with all the attributes allowed for services in that category.
      *
-     * @var array
+     * @var array<string, array<string>>
      */
     protected array $categories = [];
 
@@ -63,7 +63,7 @@ class EntityCategory extends Auth\ProcessingFilter
     /**
      * EntityCategory constructor.
      *
-     * @param array $config An array with the configuration for this processing filter.
+     * @param array<mixed> $config An array with the configuration for this processing filter.
      * @param mixed $reserved For future use.
      * @throws \SimpleSAML\Error\ConfigurationError In case of a misconfiguration of the filter.
      */
@@ -122,7 +122,7 @@ public function __construct(array $config, $reserved)
     /**
      * Apply the filter to modify the list of attributes for the current service provider.
      *
-     * @param array &$state The current request.
+     * @param array<mixed> &$state The current request.
      */
     public function process(array &$state): void
     {