diff --git a/.travis.yml b/.travis.yml
index c8cec31..dcdf284 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -26,6 +26,7 @@ script:
   - composer run phpstan
   - travis_wait ./vendor/bin/phpunit --verbose --coverage-clover build/logs/clover.xml
   - ./vendor/bin/phpcs src tests --standard=psr2 -sp
+  - ./vendor/bin/phpstan analyse src --level=7
 
 after_success:
   - travis_retry php vendor/bin/coveralls
\ No newline at end of file
diff --git a/composer.json b/composer.json
index 653b23b..f4280b0 100644
--- a/composer.json
+++ b/composer.json
@@ -5,7 +5,7 @@
         "crysalead/kahlan": "~1.2",
         "phpunit/phpunit": "^7.5",
         "squizlabs/php_codesniffer": "^3.4",
-        "phpstan/phpstan": "^0.10.7"
+        "phpstan/phpstan": "^0.10.8"
     },
     "authors": [
         {
@@ -32,7 +32,7 @@
         "phpcs": "phpcs src tests --standard=psr2 -sp --colors",
         "phpstan": [
             "vendor/bin/phpstan analyse src --level max --no-progress",
-            "vendor/bin/phpstan analyse src --level 4 --no-progress"
+            "vendor/bin/phpstan analyse src --level 7 --no-progress"
         ],
         "phpunit": "phpunit --verbose --colors=always",
         "test": [
diff --git a/composer.lock b/composer.lock
index 23eca83..7034cc9 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "8150e901ddd179befc5774ef0e72c39e",
+    "content-hash": "148ab604333c5b4aee9c13996aed11f3",
     "packages": [
         {
             "name": "monolog/monolog",
@@ -1476,16 +1476,16 @@
         },
         {
             "name": "phpstan/phpstan",
-            "version": "0.10.7",
+            "version": "0.10.8",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phpstan/phpstan.git",
-                "reference": "b7a70043d9a933c9d1575df49a7b141dbc3c469f"
+                "reference": "4f828460a0276180da76c670a0a6e592e7c38b71"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/b7a70043d9a933c9d1575df49a7b141dbc3c469f",
-                "reference": "b7a70043d9a933c9d1575df49a7b141dbc3c469f",
+                "url": "https://api.github.com/repos/phpstan/phpstan/zipball/4f828460a0276180da76c670a0a6e592e7c38b71",
+                "reference": "4f828460a0276180da76c670a0a6e592e7c38b71",
                 "shasum": ""
             },
             "require": {
@@ -1545,7 +1545,7 @@
                 "MIT"
             ],
             "description": "PHPStan - PHP Static Analysis Tool",
-            "time": "2018-12-28T13:47:37+00:00"
+            "time": "2019-01-08T09:51:19+00:00"
         },
         {
             "name": "phpunit/php-code-coverage",