diff --git a/composer.json b/composer.json
index a082553..a9a8d9e 100644
--- a/composer.json
+++ b/composer.json
@@ -25,12 +25,11 @@
     "prefer-stable": true,
     "require": {
         "php": "^7.1",
-        "beberlei/assert": "^2.6.4",
         "prooph/common" : "^4.0.0"
     },
     "require-dev": {
         "react/promise" : "^2.4.1",
-        "phpunit/phpunit": "^5.7",
+        "phpunit/phpunit": "^6.0",
         "phpspec/prophecy": "dev-patch-1 as 1.6.2",
         "prooph/php-cs-fixer-config": "^0.1.1",
         "satooshi/php-coveralls": "^1.0",