diff --git a/composer.json b/composer.json
index 0e42326..4b5a5b3 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
     },
     "require": {
         "php": "^7.3",
-        "vimeo/psalm": "master"
+        "vimeo/psalm": "^4.4.0"
     },
     "autoload": {
         "psr-4": {