diff --git a/.github/workflows/phpstan-ci.yml b/.github/workflows/phpstan-ci.yml
new file mode 100644
index 0000000..25727d5
--- /dev/null
+++ b/.github/workflows/phpstan-ci.yml
@@ -0,0 +1,23 @@
+name: Run PHPStan
+
+on: [push]
+
+jobs:
+  run-phpstan:
+    name: Static Analysis
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: 'latest'
+          coverage: none
+          tools: composer, cs2pr
+      - name: Install PHP dependencies
+        uses: ramsey/composer-install@v2
+        with:
+          composer-options: '--prefer-dist --no-scripts'
+      - name: PHPStan
+        run: composer phpstan
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 03046b9..e9a6fff 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -6,8 +6,8 @@ jobs:
     strategy:
       matrix:
         include:
-          - php: '5.6'
-            wordpress: '4.7'
+          - php: '7.2'
+            wordpress: '5.1'
           - php: '7.4'
             wordpress: '5.9'
           - php: '8.0'
@@ -16,7 +16,7 @@ jobs:
             wordpress: '6.4'
           - php: '8.3'
             wordpress: 'latest'
-          - php: '8.3'
+          - php: '8.4'
             wordpress: 'nightly'
     steps:
       - name: Checkout
diff --git a/composer.json b/composer.json
index b45b614..dcb5c11 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
     "forum": "https://wordpress.org/support/plugin/cachify"
   },
   "require": {
-    "php": ">=5.6",
+    "php": ">=7.2",
     "composer/installers": "^v1|^v2"
   },
   "require-dev": {
@@ -32,7 +32,11 @@
     "squizlabs/php_codesniffer": "^3.10",
     "phpcompatibility/phpcompatibility-wp": "^2.1",
     "wp-coding-standards/wpcs": "^3.1",
-    "yoast/phpunit-polyfills": "^2.0"
+    "yoast/phpunit-polyfills": "^2.0",
+    "phpstan/extension-installer": "^1.4",
+    "phpstan/phpstan": "^1.12",
+    "szepeviktor/phpstan-wordpress": "^1.0",
+    "php-stubs/wp-cli-stubs": "^2.11"
   },
   "scripts": {
     "post-install-cmd": [
@@ -71,12 +75,16 @@
     ],
     "coverage": [
       "php -d xdebug.mode=coverage vendor/bin/phpunit --coverage-html tests/coverage"
+    ],
+    "phpstan": [
+        "vendor/bin/phpstan analyse --memory-limit=1G"
     ]
   },
   "config": {
     "allow-plugins": {
       "dealerdirect/phpcodesniffer-composer-installer": true,
-      "composer/installers": true
+      "composer/installers": true,
+      "phpstan/extension-installer": true
     }
   }
 }
diff --git a/inc/class-cachify.php b/inc/class-cachify.php
index debe51c..41773b7 100644
--- a/inc/class-cachify.php
+++ b/inc/class-cachify.php
@@ -1073,8 +1073,8 @@ public static function register_publish_hooks() {
 	/**
 	 * Removes the post type cache on post updates
 	 *
-	 * @param int    $post_id Post ID.
-	 * @param object $post    Post object.
+	 * @param int     $post_id Post ID.
+	 * @param ?object $post    Post object.
 	 *
 	 * @since 2.0.3
 	 *
diff --git a/phpstan.neon.dist b/phpstan.neon.dist
new file mode 100644
index 0000000..ca8b085
--- /dev/null
+++ b/phpstan.neon.dist
@@ -0,0 +1,15 @@
+parameters:
+    level: 1
+    paths:
+        - inc/
+        - cachify.php
+    scanFiles:
+        - %rootDir%/../../php-stubs/wp-cli-stubs/wp-cli-stubs.php
+        - %rootDir%/../../php-stubs/wp-cli-stubs/wp-cli-commands-stubs.php
+        #- %rootDir%/../../php-stubs/wp-cli-stubs/wp-cli-i18n-stubs.php
+        #- %rootDir%/../../php-stubs/wp-cli-stubs/wp-cli-tools-stubs.php
+    excludePaths:
+        - inc/cachify.settings.php
+    ignoreErrors:
+        - '/^Constant CACHIFY_BASE not found\.$/'
+        - '/^Constant DOMAIN_CURRENT_SITE not found\.$/'