The >=4.0.0 syntax installs any version which is able to run depending on the require...

diff --git a/composer.json b/composer.json
index d6d20fd..a5b37e3 100644 (file)
--- a/composer.json
+++ b/composer.json
@@ -9,7 +9,7 @@
         "ext-xml": "*"
     },
     "require-dev": {
-        "phpunit/phpunit": ">=4.0.0",
+        "phpunit/phpunit": "<4.8.35 || >= 5.0, <5.7.20",
         "phpunit/phpunit-selenium": "*",
         "codeclimate/php-test-reporter": "dev-master",
         "ext-curl": "*",