diff --git a/composer.json b/composer.json
index 3901c0a..c5ba655 100644
--- a/composer.json
+++ b/composer.json
@@ -30,7 +30,7 @@
 	"require": {
 		"php": ">=5.6",
 		"brain/monkey": "^2.6.2",
-		"yoast/phpunit-polyfills": "^1.1.1"
+		"yoast/phpunit-polyfills": "^1.1.5"
 	},
 	"require-dev": {
 		"php-parallel-lint/php-console-highlighter": "^1.0.0",