diff --git a/composer.json b/composer.json
index 4fdadcdc860de59ded1693c6d9eac1c28782a1ae..734f6d016192663113e2a86c712b9c22a14290ad 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
     ],
     "require": {
         "php": ">=7.1",
-        "jangregor/phpstan-prophecy": ">=0.3.1",
+        "jangregor/phpstan-prophecy": ">=0.3.1 < 0.7",
         "phpstan/phpstan": ">=0.11.7",
         "phpstan/phpstan-beberlei-assert": ">=0.11",
         "phpstan/phpstan-doctrine": ">=0.11.1",